I doubt you’ll get any disagreement on your take for the controller. It was definitely an odd and experimental one, though I do remember thinking it was really cool looking when it came out. I was also 6 and not the best judge of functionality.
That having been said, the cartridge decision was in line with Nintendo’s recent plays at the time that had paid out for them in a big way, and that they continue to follow today. They had made a gamble on the Game Boy a few years prior that absolutely blew up in their favor. When the Game Boy came out, the Game Gear was it’s competitor and Game Gear had a color screen and a lot more screen real estate. Nintendo made the choice to focus on power efficiency (up to almost a half a day of playtime on four double-A batteries versus the Game Gear with about three and a half hours of play time on six double-A’s) and production cost reduction. Some of those design philosophies carried forward to the N64.
Additionally, something a lot of people seem to be unaware of these days is how absolutely stark the difference in loading times was between something like the PS1 discs and the N64 cartridge. I grew up on the SNES and N64 and when I first played a PS1 game the load times made me not want to touch a Sony console for quite a while.
Anyways, that’s my two cents. No disagreements here that cartridges held the N64 back in some ways but the tradeoffs made it an amazing system and miles above the competition for me, personally. Good gameplay and quality of life will always beat more power in my book.
I’d argue the two greatest barriers for the average, non-STEM individual adopting metric in America is the speed limits being in mph and the temperature being in °F. Both are convertible easily enough, but when you constantly have to do so to engage with critical infrastructure or safety (cooking temps, etc.) It provides a barrier against adoption for anyone without the drive to make a concerted effort to use metric.