should i buy overwatch?

Well it's not a waste if you think you'll enjoy it.
For me I don't really like playing alone so if I didn't already have the game I'd personally only buy it if I had people to queue with.

There is usually free weekends where you can try the game out, I'd suggest waiting for that if you're not entirely sure. Or wait for a sale if you don't wanna waste as much money incase you wouldn't like it.