What exactly even is Identity Security Level?

So I was wondering why the Security Level improvement takes so long.
It does not seem to use a lot of resources.

It doesn’t even seem to stress one thread.

some more from Libre Hardware Monitor


So what I found is that non of this gets stressed at all while increasing security level:

  • CPU at all
  • GPU in any way
  • drives (neither write nor read or anything at all)

Those were up to now the only limiting factors in all of my own programs.
So unless I missed something I feel like the security level increment process is intended to just be really slow and not actually do anything.

So I can only feel like the security level has nothing to do with actual security but rather what time one invests into the identity. Please correct me if I’m wrong.