iPhone/iPad good as a source, or get a streamer?

This is probably a dumb question with a simple answer I’m just missing, but here goes. I’m currently using my iPhone and iPad wired with a Camera Adapter to my DAC via Qobuz in my headphone setup and it sounds good, but I’ve wondered if using a streamer (on the level of an Optical Rendu or Innuos Zen Mk3) would be better as it’d be plugged directly into the router. I’d assume the latter would be better given the wired connection vs. WiFi, but wondering if anyone has compared that to connecting an iPhone/iPad directly to a DAC? Location isn’t a huge deal since I’m in close proximity to my router anyway. Thanks for any thoughts/experience/suggestions.
I have always considered phones to be mid fi at best.   The fact is, most folks who use their phones to stream music are streaming mpg or AAC files, so high end is just not a question.
Yeah I’m not using the DAC in the phone so I suppose this is more a question of the best way to stream music and how much improvement using a streamer wired to my router would make. 
iDevices have surprisingly good sound quality when bypassing the on-board DAC as you’re doing. That said, to my ears streaming via my microRendu > DAC sounds better than my iDevices into the same DAC using the CCK connection. It’s noticeable, but I wouldn’t say it’s a night and day difference either. Moving up to an opticalRendu or the Innuous .. I can’t offer you an opinion, unfortunately. No doubt someone will say there’s a massive difference. Massive. Veils will be lifted. Veil upon veil in fact. My advice is to take advantage of gear that comes with a trial period. Best of luck.
Thanks @melvinjames.  Yeah that’s about what I would’ve guessed, and it’s nice to have some confirmation.  Given what I’ve read here, unfortunately moving to the better streamers does seem to make a meaningful difference.  Or maybe I’ll just try a Raspberry Pi to test the waters first.  It’s a journey...
I just went through this and got a Pro-ject Stream Box S2 Ultra. It definitely sounded better than my iPhone. Other potential improvements that I've found to have good ROI in terms of improving sound quality of my Pro-ject streamer are:

1. Turning off WiFi and using an Ethernet cable
2. Getting a better quality Ethernet cable (Supra Cat 8 has worked well for me and was a notable improvement over an AmazonBasics Cat 6 cable)
3. Getting the right USB cable. The Phasure Lush is working really well in my system.
Thanks @calvinandhobbes.  Just curious what DAC you’re using and what kind of improvements you got with the Pro-ject?  I assume you were using the Apple Camera Adapter out of the iPhone?  Thanks again. 
@soix I was using the Apple Lightning to USB 3 Camera Adapter with the iPhone. I'm using a Denafrips Ares II DAC. These were the improvements that I heard when using the Pro-ject streamer versus the iPhone:

- Broader & more 3-dimensional soundstage
- Better resolution of complex musical passages: Electric bass in Blue Moon Revisited on Trinity Sessions, Cowboy Junkies & Waltz for Debby, Bill Evans Trio
- Tonal colors are more evident
- Notes seem to hang in the air longer. Reverberations continue instead of being cut off.
- More presence around voices and instruments.

The improvements sounded quite significant to me & turning off the WiFi further improved my perception of the sound quality.

Excellent feedback!  Thanks @calvinandhobbes.  I’ve been told by people knowledgeable in the field that a wired connection to the router is always preferable to WiFi, but there are also a lot of people here who say as long as you have a good WiFi signal and there are no dropouts that it’s just as good as wired.  The benefits you describe are very high on my “must have” list so I’ve decided to definitely give wired a try.  Thanks again for your very helpful thoughts. 
Just use the phone it sounds fine. I pretty much use an iPhone hooked to a mojo. The mojo poly looks nice too. It would turn the mojo into a “steamer” if you wanted. 
I failed a blind test of my Mac mini hooked to the mojo via tosslink and the mojo hooked to the iPhone. Hard to tell the mojo/iPhone from my benchmark DAC3 hooked to a Buruson amp too. I should probably turn in my audiophile card now....

@soix In addition to using an Ethernet cable from a WiFi extender, these are some other things that I did from which I heard a clear improvement. (i.e., so clear that I didn't even need to A/B test the sound quality...I knew right away)
  1. I tried both an AmazonBasics Cat 6 Ethernet cable and a Supra Cat 8. The improvement with the Supra cable was about 50-75% of the magnitude of improvement by going to Ethernet
  2. I added an Audioquest Jitterbug to the USB output from the Pro-ject streamer. The USB from the Pro-ject is supposed to be optimized for noise so I was more than a little skeptical of the benefits from doing this. But, the increased smoothness and clarity was evident.
  3. I tried 5 USB cables (free USB cable from an HP printer to see if cables make ANY difference at all, Belkin Gold cable, Pangea Premier SE USB cable, Shunyata Venom cable, Phasure Lush cable). For an almost free option, the Belkin was okay, The Shunyata was clearly better. And the Phasure Lush was the smoothest sounding with the best resolution and the best at conveying the timing of the music. I LOVE the Phasure cable compared to all of the rest. The Shunyata is good, but the sound quality from the Phasure is at another level altogether.
I just been messing around with this on my iPAD when I discovered that on Qobuz app to get anything better than CD quality you have to download the track local. I am using lighting to USB A connector and Pangea cable. to DAC. The local files (>Redbook rez) sound purdy dang good but my dedicated streamer has a little more weight.
But I think for people with integrated amps and CD players with a DAC who want to get into streaming to test the water an iPAD is a great way to get started as apposed to buying a Bluesound Node. Which seams to be the default answer here when people ask about getting into streaming.  Then if you move up to a dedicated streamer you got a nice controller.
I just been messing around with this on my iPAD when I discovered that on Qobuz app to get anything better than CD quality you have to download the track local.
That’s not been my experience.  I get up to 24/96 out of the Lightening port when streaming, unless my AQ Dragonfly Red is lying to me about the resolution.