I used to bartend. I've taken those classes but honestly I don't think they help much. Only fundamentals like shot pouring and a couple of basic drinks. Do it but know that most bars or restaurants you work for have their own set menu and prefer their drinks a certain way.
So you may be used to pouring beer and shots in a bar, then in another place you may find its margaritas, mojitos etc depending on the specialties.
So most places you'll want to work will want to train you for their drinks if they have specialties. And most people won't hire you based on the bar tending course you took. It's easier to get in by waiting tables in a place then transitioning to bartending so you know the food menu as well. But that route is also competitive cause all the waiters want to do it. And they already know the menu and prices better than you.
But there some places which will hire you though. My first gig was red lobster. I never waited tables for them. But later gig I waited tables then bartended. Later I had enough experience I could apply straight for a bar tending gig