I've sold all my Xbox One games + a lot of B/C 360-games and repurchased the ones I want digitally.
For Switch I decided to go digital from day one. I bought Bomberman physical because the publisher told me they only had 20,000 copies made for Europe, but I'm guessing there was a reprint, because they're everywhere now.
Besides collectors editions, I'm not buying another physical game - disc or cart, ever again.
And for Switch the answer is obvious, having your entire collection available without carrying dozens of cartridges is just practical. It's all about convenience for me, and having everything available without the fear of losing or misplacing, which always is a problem with handheld systems.
And the boxes just feel like big empty shells now, nothing to collect there. More shelf space for amiibos