Is it possible to remove Snapd with Glib libraries completely without ruining the system?

These packages are designed to allow applications to communicate with snapd. One accordingly would believe that these packages are not of any use of snapd is not anymore installed. However, in order for an app to be able to communicate with snapd, the app must be compiled with support for these libraries. These libraries thus become a hard dependency of these apps, and must stay on the system even if snapd is removed.

That is the technical reason. However, what functionality (non-snap) applications gain by being able to access snapd is unclear. All descriptions of what the libraries do boil down to

snapd-glib is a library to allow GLib based applications access to snapd, the daemon that controls Snaps.

Possibly, these are what would allow these apps to access to the Snapd REST API in order to interact with snapd.