2K18 XBOX - disc still required after install?

I'm a total console noob and haven't had one since Nintendo 64, preferring PC. I switched over to XBOX One only for 2K18 because of the rampant cheating.

My brand new XBOX is behaving weirdly - first it wouldn't recognize that I inserted the 2k18 disc in it, When I reset a few times and finally got it to auto recognize and install the game, it is still requiring the disc to be inserted to start and play the game. Is this normal? This is 2017 for Pete's sake, everything should be digital.

Random thoughts on xbox:

1) The long load times compared to the NVME SSD's on my PC are a minor annoyance, esp when you simply want to exit back to the Neighborhood.
2) the framerates are lower and jerky and the res looks poorer
3) hate that I cannot use my 21:9 widescreen and have to have black bars on the side

Yes, physical copies on consoles require discs. This is because you can sell the game, but not to let you keep it after you sell it.

Same deal with the PS4. Games will install to the hard drive for faster loading times (in theory), but you still need the disc as an anti-piracy measure. Only way to avoid that is to buy the digital version, which tends not to be any cheaper and takes longer to install, but does offer some convenience. I realise that's also not particularly helpful to know after you've already bought the disc version, but for what it's worth, you can go digital only on the consoles. It's very easy to fill up a hard drive very quickly, though.

Arrggh. Oh well, this is the least of my complaints about 2K18.