My thing (I’m not the guy you replied to) is all the various user-facing complaints that I tend to see in these discussions. I use a distro where I can get current versions of anything I’ve ever needed, and I know how to maintain my system.
As a user, even if the various alternatives are fine most of the time, without concerns about security, integration, etc - I’ve never read anything that would make me want the additional complication. (I say this recognizing that there are security concerns regardless of how you get your software - I’m not saying these new solutions are inherently worse in that regard.)
I suppose at some point I’ll want or need to embrace flatpak/appimage/snaps, but I can’t find any reason I’d do so now - it feels like it increases the number of gotchas I need to worry about when installing software without actually giving me anything I want that I don’t already get with my “legacy” package manager.