British supermarkets mostly require the use of their app to self-scan. You need to either use your phone or use your app to start the scanner. Once you have done that it works OK. A bit error prone.

The other problem is that, like self checkout, it often requires human intervention (buying alcohol or high value items, for examples) still requires human intervention. This can require a long wait at the end. I once got so sick of waiting that I left my shopping and walked away and went somewhere else.