Credsticks were working before the wireless matrix was a thing (and so before everyone had commlinks). The technology is solid enough that they still get quite a bit of use.
I've not seen it spelled out so clearly, but I think they come in two flavours:
- ones that are attached to an identity (likely largely superseded by people just handling routine transactions with their commlink), these would always need authorization from the owner in some way to permit a transfer
- certified credsticks, where the value is held purely on the cred-stick, not attached to any identity or account. A bit like cash, a bit like bearer bonds, a bit their own thing.
Personally I always thought that certified credsticks should only be a shuttle, not something you move money on and off of regularly. That 'certified' bit being that it was certified by a financial institution, in some manner, that this much value was put on this credstick. So when you check the value on one you see both the value and the certification. However I'm pretty sure that the fluff has people using them more like pre-paid visa cards, able to take a certified credstick and buy drinks with it, pay a taxi driver, etc.