With open source apps though? My guess is the idea of a store is a commonly known UX (App store, Play store.) And the snaps give you a way of installing more updated versions of software than the package repos provide.
I'm fine with the repos. After all what am I using? Firefox (I know how to switch to PPA), Thunderbird (with the features that were there 10+ years ago), LibreOffice. Slack is a snap and customers use it. Server side stuff is usually docker. Languages have their own package manager or an asdf plugin. Emacs is apt-get. Is GIMP still an apt? It seems they are going for flatpack https://www.gimp.org/downloads/ Not a fan of that too.