Powerlifting as an addition/complement to your TRI training

I know nothing about powerlifting/weightlifting, and in the past I assumed it was only to make your muscles stronger, so that you could lift heavy stuff.

Recently, more and more people from my climbing groups kept telling me how powerlifting has helped them get stronger with climbing.
I am starting an intro training tomorrow and am looking forward to learn new things - and get stronger... and am starting to wondert if it would also help me with swimming/biking/running.

Obviously, I am expecting an initial response to be YES, but those of you who do lifting - can you share how exatly it's been helping, what are your "newbie advices", and what to do to get the most of it as an addition to other sports.

And since this would be my fifth sport, it's impossible to devote too much time for it. I can imagine 1 - 2 times per week. Any tips for nutrition and anything else I should consider - truly appreciated.