As a user, the best way to handle applications is a central repository where interoperability is guaranteed. Something like what Debian does with the base repos. I just run an install and it’s all taken care of for me. What’s more, I don’t deal with unnecessary bloat from dozens of different versions of the same library according to the needs of each separate dev/team.
So the self-contained packages must be primarily of benefit to the devs, right? Except I was just reading through how flatpak handles dependencies: runtimes, base apps, and bundling. Runtimes and base apps supply dependencies to the whole system, so they only ever get installed once… but the documentation explicitly mentions that there are only few of both meaning that most devs will either have to do what repo devs do—ensure their app works with the standard libraries—or opt for bundling.
Devs being human—and humans being animals—this means the overall average tendency will be to bundle, because that’s easier for them. Which means that I, the end user, now have more bloat, which incentivizes me to retreat to the disk-saving havens of repos, which incentivizes the devs to release on a repo anyway…
So again… who does this benefit? Or am I just completely misunderstanding the costs and benefits?
It benefits both devs and end users.
Many people don't have the time or resources to manage a broken application especially devs who have to deal with that on several Linux distributions simultaneously.
Many distros use different package install scripts and repos to suit their specific needs. If I were to use a Debian-based distro, I would need to use apt to grab from a Debian-compatible repo. If I somehow got apt to work on Fedora, then not only would the program I installed not work, it would likely annihilate many of the preexisting dependencies and possibly brick the system.
I personally use Arch Linux which uses pacman, my package manager of choice, and a lot of times I'll find an application that doesn't work on my system due to mismatched dependencies. Arch is incompatible with .deb and .rpm files and does not use the Debian repo and its derivatives. It uses the AUR and its own derivatives of that repo. I don't have the time or skill to get a program to work with a newly updated dependency on one distro nevermind however many exist on the internet. Many devs do that for free after they've been working at their job for hours and/or taking college courses.
What a Flatpak or appimage (ignoring goofy aah snaps) really does is allow a developer to update dependencies for their application at their own pace without having to play catchup when something inevitably breaks due to an update. It allows for a more stable system. As a Debian Bro, you might not need that, but on rolling-release distros like Arch and funky distros like Manjaro that can be very much welcome.
Yes I enjoy that extra stability and organization, especially as I use a rolling distro as a gamer. Hearing talk about Flatpak I disliked it but I decided to try it out after Steam Native bugged due to a system library update. I enjoy it now also because it feels good that installing apps don't get a root password and scatter files everywhere they please in the system.
Bloat is often held up as the ultimate evil without further ado, scaring everybody. I think a little extra disk space would be more concerning on an embedded system. Snap is also aimed at embedded systems btw.