Why do people play a lot of tables at one time

Just gradually add tables as you become more comfortable.

Another thing that may help is to stagger the start times, so you dont end up on 6 bubbles at once trying to make a bunch of difficult decisions.

More tables mean more hands, more spots, and potentially more profit over time. It can also stop players from getting bored or overthinking every decision.
The downside is obvious: if you add too many tables, your focus drops and mistakes go up. Multitabling only works if you can still make good decisions consistently.

I used to do that a lot, playing at multiple tables simultaneously. I don't do it anymore, though, because I prefer to focus on a single table where I can better evaluate my opponents' actions.

poker is a game of clicking buttons that's why people play a lot tables same time.