My father had a manual when I was learning to drive, and he required me to spend as much time driving his car as I did my mother's automatic. He only told me about the hill and hand brake thing because I was struggling, but also said I shouldn't do it except on really steep hills, as it wears out the brake.
I've always considered it cheating, tbh. But when I first started to drive a manual in Europe, I was in Switzerland with a giant, 20 year old Audi 100. On the very steep ramps where I got stuck in traffic in parking garages, it was a godsend. I quit doing that, except in exceptional circumstances, once I got rid of that boat!
I don't use it now, due partially to having good clutch control (my instructor once commented that my clutch control was as good as his...) and my current car has a pause which holds you in place when you're on an incline to hold you. I find that annoys me far more than it helps, but there's no way to disconnect it.