I'm not young, but joined the computer revolution with my ZX Spectrum as a young teen and my interest in technology has never diminished.
Life in the UK is now largely cashless and can be months on end before I draw cash from an ATM (Apple Pay et al rules the roost now). I always keep ten or twenty quid in my wallet for emergencies and a few pound coins on the side to tip the occasional fast food delivery driver, but that's about it.
Thailand is catching up on the electronic payments front, albeit slowly. QR codes do the job for me linked to my Bangkok Bank account, although still not as smooth as an Apple Pay purchase. There's hope yet.