Same problem with proton. Payment terminals needed to ask the consumer if they wanted to pay with proton or debit, and that added a few seconds of delay for the processing of every customer, which actually cost a lot to big supermarket chains, more than they saved with proton, and thus they dumped proton, and everybody followed suit.
Their functional successors, Itsme and Payconic have on the other hand great usability and thus have achieved much bigger successes.