UK user experience
Was able to by 1 day passes every day for my 3 days stay in Rotterdam. Payment is straightforward with apple /Google or Samsung pay. This is important to know as international debit card don't work in public transport in Rotterdam and credit cards will incur extra cost. The app doesn't quite help differentiate the RET transport (metro/tram/bus) vs national rail unless u spend some time understanding the system and logo for each transport mode when u look for itinerary from point A to B.