Since the site was unusable and I wasn't able to look up the study they cite I'll have to make a small assumption:
Based on the date of the article, I assume this mostly precludes contactless payment. As a personal anecdote, a salad place I know in Berlin recently switched over to card-only and they specifically encourage and educate people to make use of the contactless payment feature thats enable in most debit/credit cards Germans have. They went from unmanageable long queues that made eating there a chore to almost no queues and one of the fastest ways to pick up food via that single change.
Based on the date of the article, I assume this mostly precludes contactless payment. As a personal anecdote, a salad place I know in Berlin recently switched over to card-only and they specifically encourage and educate people to make use of the contactless payment feature thats enable in most debit/credit cards Germans have. They went from unmanageable long queues that made eating there a chore to almost no queues and one of the fastest ways to pick up food via that single change.