IF you only have 32GB of storage you won't be doing that anyhow.
On some level it doesn't really matter, it stinks but it doesn't matter.
That said it might affect the camera performance in the long run, but then again if you are going to film 4K and take tons of RAW photos get the bigger storage since it's not expandable.
Depends on your use case for your phone - I usually copy 20-30 GB of videos to my iPhone 6S(using VLC) on a fairly frequent basis - for some reason it's my primary way of watching TV shows. The saving grace here, is that with only 32 GB, there is a pretty hard limit to how much you can copy before you just run out of space.
I think this really depends on how long you are expecting to use your phone. Presently the iPhone 7 feels unnecessarily fast, but in 2-4 years when more data is consumed and operating systems are more taxing, I may care more about those difference.
How can something feel unnecessarily fast? It may be unnecessarily fast but to me tech never feels fast enough. Unless it would respond before I do something perhaps... I'd like lag to approach zero to be honest.
Because of programmers and Hardin's "Tragedy of the Commons." Coders will always use the computation, memory, and bandwidth resources that are there. "If I just use a little more, it benefits my app, but it hurts everyone else just incrementally." Everyone makes the same calculation, and voila, the machine that's 2X faster feels just as slow. It's the same reason why building more highways just results in more people stuck in slow traffic.
In the real world, the flash speed difference is rather insignificant. I don't copy around huge 4K movies on my phone very often.