They usually have a higher bitrate than you can get from streaming. There's not one CD I have that I immediately tell the difference in quality of I switch between streaming (or even a standard mp3 actually) and a CD. CD wins every time.
Most of the records I buy come with bandcamp codes. I can play the flac files if I want digital audio, physical media for me is about the thing itself. Often get full sized posters and patches. Shit I'll buy a tape over the cd too