Newbie question about Vault 2i


I am about to order my new home theater and I am planning on buying Vault2.  I have Ethernet set up in closet where the gear is. 
I am planning on converting my CD’s and also signing on to either Tidal or Qobuz.  
The way I understand it is whatever music I download will be stored on Vault until I drop service.
Vault will be connected to my new receiver.
I will access the music via my iPhone and iPad, correct?
will a subscription to Roon make it easier to use Vault or is the software easy enough to use. What is the Value of using Roon?
Would converting to FLAC be the best option. 
Is connecting to receiver via rca cables to analog out the best way to go
if I didn’t care about converting CD’s would Node 2i be a good option for a lot less money? Is there an advantage to storing Tidal files and Qobuz on on Vault rather than just streaming Tidal to Node 2i.
thanks 
Bob

galleybob
I am original poster. I want to thank everyone who took the time to educate me on streaming and Bluesound. I knowledge level on streaming was zero when I started to look into Bluesound.
I have a Bluesound Node 2i. I took the advice and decided that my Apple Superdrive was good enough and that I did not need the Vault 2i.
I bought a Buffalo Network drive that was surprisingly very inexpensive. It took awhile for me to figure how how to set it up but once I did it I found it to be a great way to store and stream my CD's. Instead of using Apple Music to do the conversions I now use dbpoweramp which converts to Flac.
I thought the best way to connect Node2i was analog with the provided RCA cables. A few days ago I bought an optical cable so now I am using the DAC from my 1120 Anthem. Sound now is amazing. I stream Tidal and my CD's. Not sure if the Anthem has the ability to process the Tidal MSQ files or not, but they sound great so I'm not sure. My next step is to do a trial of Qobuz and see how it compares to Tidal
Galleybob, Glad to hear your getting good sound. You have to have an MQA enabled device to stream MQA files. IMO some MQA albums do sound fantastic!
I am doing a trial of Qobuz now. Sounds great, sometimes amazing depending on the recording. Will have to do A/B tests with Tidal to determine which streaming service I go with