Why the fake referendums in Ukraine?

I guess I'll never understand totalitarian regimes:

Officials in Russian-occupied territories in eastern and southern Ukraine were forcing people to vote “under a gun barrel,” residents said on Saturday as staged referendums — intended to validate Moscow’s annexation of the territory it occupies — entered their second day.

What's the point of this? Everyone knows what's going on, and Moscow is hardly even making an attempt to pretend the referendums are real. Should we take it as good news that even a thug like Vladimir Putin feels like he has to at least symbolically carry out the norms of democracy?