Any audiophile use computer (MacBook) as your audio streaming source?

The challenge with a Macbook, along with any other PC is the potential for ground loops via USB and noise from the power supply.  Fix those two issues and they can be excellent.

Many high quality DAC's now are galvanically isolated USB inputs, so that's often not an issue.  The next issue is if your charger creates too much noise.  easy to tell by unplugging the charger from the wall and listening. This also eliminates ground loop issues, which may only occur with non-portable PCs.

They are all computers, but some more optimized than others.

If your preference is to use your MacBook, and not switch to a purpose built streamer, then inserting a DDC in front of your DAC for galvanic isolation and reclocking could provide noticeable benefits.  You could try this one, which can also be used as a streamer, but there are also less expensive options like this one, or this one.

Another option is to use a networked endpoint as the interface.  The PI2AES is an option that can be improved with a power supply upgrade and maybe Fibre Optic networked isolation.

https://forum.hifiguides.com/t/streamer-ddc-showdown-pi2aes-vs-sotm-sms200-ultra-neo/15025

I used a MacBook years ago. It isn’t even close in sound quality as a dedicated streamer. I had run on battery, shut down all apps… etc. no where near a good streamer. I recommend Aurrender. I have owned and auditioned in my system a number of different ones from $2K to $22K. In general, you get what you pay for… the more you invest (not arbitrarily) the better the sound. My great vinyl leg, CD, and streaming sounds the same. That is what the state of the art is today at most price points. 

Re lossless etc., it will depend a lot on your software config, i.e. through web browser (poor), dedicated app (depends), or something like Audirvana/Roon (can be excellent). 

Re computer vs. streamer, once you get an external DAC, the streamer (with built-in DAC) argument evaporates. Needless to say, there are different levels of external DACs, so your choice.

IMHO, streamers are utterly overpriced for what they are, and you have to take the DAC that the manufacturer slaps in there. The whole "optimized OS for audio" is marketing hype, considering the minuscule computational power it takes to play/decode/transform audio signals compared to processor power in current computers. I assume you do not intend to run it on an ancient MacBook 140 from 1985. You can look at the activity monitor when playing music, and it is insignificantly different from when nothing is playing. I also assume this would be a dedicated computer for audio, you're not also 3D rendering while trying to stream music.

I use a Mac mini as a Roon server, and that gets distributed.

1) USB to Holoaudio May DAC L2 [I challenge any streamer on audio quality] in listening room.

2) LAN to computer with older Topping D50 DAC (computer workstation with bookshelf speakers & headphone rig)

3) LAN to Laptop with dongle DAC and earbuds for couch surfing.

4) LAN to Living room in-wall speakers through a Rotel RA 1572 integrated with built-in DAC.

Audio quality is fine in all cases, considering limitations of various set ups: in-wall speakers do not produce a soundstage like my listening room, but perfectly enjoyable when I cook. etc. etc.