I've had a few buddies work two jobs...
Starbucks by day Olive Garden by night...
Is it worth it ? Well it all depends on your circumstance... if it was me I would just work 1 high end serving job and have a side gig.
A lot of restaurants allow you to give up and pick up shifts by computer. Thus allowing to tailor or create your schedule. Instead of working two serving jobs I would work 1 serving job and get a well paying side gig. I've had co workers that were
*Part -time models
*Band members that would play in clubs (Getting $60 - $300 a night)
*Referees for for baseball games. (Getting $100 a game)
*I used to sell stuff on eBay
*Right now I own vending machines that bring in an extra $100 a week
*I have a friend that would dj $100 per 2 hours.... but most of the parties he would do would only last 1.5...
iif you are hungry enough you can turn a hobby into some extra cash no need to be tied to a second job which can create conflicts with schedule.