I think the earlier powerlinks (8 speeds?) were made to be reusable. The 10 speeds aren't, but while I definitely haven't figured out how to do it with my fingers only, I have managed to jury rig something to get the powerlink apart and reuse it several times (it usually involves balancing one end of it on a ridge (the ridge sits on the inside part and not on the outside) and then using something else with a ridge to push down the top part of it only on the inside, squeezing it together. sometimes jeweler's screwdrivers or tiny needlenose pliers get used. )

I switched to using sram chains & powerlinks once after my chain broke at about sunset when I was 7 miles from home. It was a long walk home (I didn't think I was going to be able to jury rig something in the middle of nowhere while it was getting dark). While I had a chain tool & a spare pin on my bike tool - it was either an 8 speed or 9 speed pin and the chaintool was for bigger pins than 10 speeds - so it was useless anyways. So now I always carry a working chain tool and a spare power link.