I’m using a 2008 dell now as my ‘primary’ PC and no I don’t worry about using snap packages; though tend to avoid them if I can easily, but this is not the sl510 you mentioned (this box has 8GB of RAM).
I can’t compare snap versus flatpak as I don’t use flatpaks normally thus have nothing valuable to offer sorry there.
On the sl510 with its 2GB of RAM, I’ll put more effort into avoiding snap packages than I do on boxes with more RAM, but my experiences are that
- snap packages are not slow to execute/run; they feel ~equal in speed
- snap packages can be slower to start; especially for some releases (this has been improved!)
- snap packages provide security benefits that I do consider in deciding if I replace them
- snap infrastructure does slow logins
I also consider the ease of what I call upgrade via re-install (or Lubuntu calls it Install using existing partition in the understanding checklist doc) and having non-deb packages complicates that. If I recall correctly; the only non-standard thing the sl510 has is encrypted home, which Ubuntu no longer offers at install time, but can be used by only adding a package pre-install. This allows me to change release & use it for QA on a different release, but still have my own files that exist on the device.