unusable for guests
Without an account, it is not possible to pay with the app using common payment methods (e.g. credit card). Creating an account (and receiving a payment card) is also impossible as a guest. Either the hosts provide guests with a payment card or you have to think of alternative ways to get rid of the garbage. As a guest, try to hand in your rubbish early and test whether it works for you so that there are no unpleasant surprises on your departure day.