They think it’s nice way to install command-line tools. I think that only spoil the idea of immutable system as a desktop OS, where ideally everything could be reduced to a single installation method.
That’s why I use the original Fedora Silverblue and have no interest in uBlue derivatives. Actually I want a more simplified base system and not more bloated one.
And yes, Flatpak is enough for everything (mind about Termux on Android).