There's a part of me that thinks that I should get Persona Q2. It may end up being the last 3DS physical game and almost certainly the last good one. It may also end up being rare and collectable due to being released so late and also being an Atlus game. But I feel like in order to fully "get" the game I need to play Persona 3, 4 and 5 which I don't have the time for. I figure without that it would be like SSB being your first ever Nintendo game - still a fun game but not nearly as special if you don't know the references.
The 3DS had a hell of run. 8 years is pretty exceptional and only the most successful systems have those kind of legs. I think it's one of Nintendo's best systems and will likely be remembered fondly. Personally it also gave me a new appreciation of the DS, which I initially wasn't much of a fan of. With the 3DS I stuck mostly to RPGs and visual novels, cherry picking the types of games I feel work well on a handheld. Because of the backwards compatibility I ended up digging into these genres on the DS as well. With the DS I had stuck more to the big mainstream releases like Mario and Zelda and wasn't impressed. Turns out I had just been playing the wrong DS games and the different approach I took with the 3DS let me find a strong niche of titles that appealed to me on both it and the DS.