I'm skeptical of those types of systems. From an efficiency and ease of use perspective they make a lot of sense if they work properly. I'm sure that they reduce line ups a great deal which is awesome and probably also help with theft. The parts that I don't like are:

1. paying additional money for the system. That just seems crazy to me, especially since most cards are tap to pay anyway, which is the same as a tap to pay wrist band. The system is basically just an extra way of making money for the festival. Its the equivalent of forced purchase merchandise.

2. The reimbursement part. I don't know how it works exactly but in my opinion that part needs to be absolutely simple and user friendly. I feel like a lot of people won't be bothered to reclaim small amounts or people may lose their wristbands or something before trying to reclaim. A person forgetting or abandoning a small amount like 2-5€ isn't a lot for the individual, but on a massive scale that translates to a lot of money for the festival. If the reimbursement process is as simple as pushing a button then that's cool. If it involves making a phone call or going to a special kiosk in the festival that is hard to find or has any line up whatsoever, then I think its bullshit.