The idea is good I think but the implementation has only ever caused me problems and seems to have a bunch of frustrating edge cases.
I’ve been using snaps for a few years now and while they still could use some improvements, the snaps I’m currently using seem to be fairly indistinguishable from deb-based packaging thanks to bug fixes they have done over the years. I think the idea of containerized applications is a good one, I think it actually can be safer. Performance is also fine for me with snap applications even like Firefox snap startup speed, although I’m using an R9 5900x and Gen 4 M2 NVMe SSD so maybe that’s why, or maybe they really have improved the snap software and it is just as fast now for the most part.
I’ve had to swap Firefox on my laptop for the deb package, the snap took like 5sec to open, whereas the deb opens instantly. Other than that, i don’t see much of a difference, but i run into sandboxing issues quite often (same with flatpak though)
