That makes perfect sense.
I've also gone relatively low on storage because I don't mind managing it (ie: deleting device copy of videos or photos if I have tons).
Sometimes, however, I come across a new use for my phone I never really applied before. This summer I was preparing for a wedding and got into Spotify, and ended up downloading a lot of music at a high quality level to keep on my device. I ended up clearing up my cardboard apps and as much other stuff as possible to make ~10G for Spotify on a 16G nexus 5. It was the first time I felt constrained by the space of my device since I got the nexus 5.
This time around, 32GB was the minimum i'd get. I was definitely tempted by the 64GB option, but I'm buying two phones so I figured I'd just get them at 32.
I could see wanting 64 or 128 if you were planning to take a lot of movies with the device. I'm not sure how good the microphones are for movie capture, but the video itself looks to be pretty decent. I think I'd do most of my movie capturing on my SLR with hotshoe mounted microphone, though it doesn't do high framerate capture (I'd have to lower the framerate to get slow motion).
My phones didn't ship yet. I expect they'll ship Monday or Tuesday and I'll get them Tuesday night when i get back into town or else Wednesday. Even if i don't get them until Friday it's not a big deal.