The good: Snap packages run on almost any Linux distribution, so they're an easier target. Distribution specific packaging can be tedious, and often involves a distro having to maintain packages themselves by repackaging the "upstream" package or software. With software that updates frequently, snaps theoretically mean a lot less work for distro package maintainers, because one package works on every distro. Snap packages are also sandboxed and have less access to the host system.

The bad: In practice, they don't work very well. Snap programs are slow to start up. Because of their sandboxing and universal nature, their integration into the distribution can be lacking.

For example, when I upgraded to Ubuntu 22.04, I was automatically moved to Firefox snap. It is painfully slow to start. Instead of the normal Ubuntu file browser when I went to upload or save a file, it uses a jarringly different file browser. I switched back to using the firefox PPA, and now this new package directly from firefox.

I also moved to the Slack snap, which also works terribly. I apparently can't upload and download files from it reliably, so I have to open it in my browser to do so. There appears to still be an official deb package, but they've hidden it on their site because they want you to use the snap.

Snap started as a method of packaging applications for servers, and that's still where they're most useful. Slow startup time and issues with desktop integration are not concerns for server side snap packages. For desktop graphical applications, Flatpak will likely be a much more useful universal package system.