I have installed a couple of applications using snapcraft, and I no longer want to install any applications.
So I wonder if it is ok to delete snapcraft without the applications being removed.
Snnapcraft is a tool to build snaps. You probably meant snapd, which is what you use to install snaps? In that case, on Arch/Fedora/OpenSUSE removing snapd will also remove the snaps. On Ubuntu/Debian removing the snapd will not remove snaps right away, but there’s no guarantee those snaps will function properly (apt remove --purge will remove snaps and whatever remains).