The hearings aren’t useless. None of this is useless if you’re a Democrat. They are running out the clock. Even if DJT gets reelected they will keep distracting him and the country until they can regain power. That has been the strategy from day 1 and it’s working.
They can keeping doing these stunts, while he reshapes the judiciary.
Win/win
Especially to the Russians, if as Hill testified their, real objective was to sow discord & mistrust of the system.
It has been successful beyond their wildest dreams.