I only use rolling releases on my desktop and have ran into enough issues with apps not working because of changes made in library updates that I'd rather they just include whatever version they're targeting at this point. Sure, that might mean they're using a less secure version, and they're less incentivized to stay on the latest version and fix those issues as they arise, but I'm also not as concerned about the security implications of that because everything is running as my unprivileged user and confined to the flatpak.

I'd rather have a less secure flatpak then need to downgrade a library to make one app I need work and then have a less secure system overall.