When I first began learning how to play pool, the guy who was teaching me had a saying (he actually had many sayings, lol) "banks and combos are low percentage shots"... with the meaning to look for higher percentage shots, when possible. I still hear him in my head when shooting banks or combos.
That having been said, he could shoot both very well, when needed. His lesson was not lost on me.
I don't practice anything nearly enough, let alone combos. Had I the time to practice the way I would like to, I think some dedicated combo practice would be a good idea. For me.
Practicing the tough shots is like practicing on a tough table. It pays dividends on the easy shots too.
Hu