I truly believe that the ATV 4K is the pro version
I personally believe that you DO need the 64GB. Just look at the original wording on its website - Apple stated that "If you plan on streaming 4K film, then go for the 64GB" surely this is wise as the film caches temporarily. Therefore a two hour film is around 20GB now lets assume Atmos will be added soon and maybe just maybe next year Apple launch a slightly larger file size for the faster broadband users = 30GB before you know it.
Now include screen savers at 500MB each - say you have 10 = 5GB, then the TVOS at 3GB, then favourite apps totalling 3GB and then a few games and TEMPORARILY you're at 45-50GB.
Surely it's always a great thing to have a lot of breathing space??? I can't see why the debate when the top spec is 20dollars - just 20!!!!!! more. Seriously guys, it's better to have too much than not enough. I bet known who bought a 256GB iPhone (myself included) has ever regretted that. I did on the other hand spend 5 years fighting with my old MacBook for space that I really really needed. I never want to go through that again!