I actually do, love UHD blu-ray, can’t compare to anything downloaded actually. Level of compression and haptics, physicality, etc.
That said, it’s not great for the environment, probably still worse even when comparing with the ecological footprint of data centre infrastructure (download-and-keep would be even better than streaming actually). Not everything gets a (timely) release either.
Sometimes a quick download would be great. FWIW I’m on a 400mbit/s connection.
Obviously DRM free versions would be the cherry on top and would guarantee “portability” into the future (I’d still buy the n-th version of The Terminator in 8K in any case ;)