Since mid July, passengers were able to enter through the previously closed front door of the bus again and buy tickets from the driver, but only with electronic "contact less" payment methods, such as credit or debit cards for example, or mobile apps (Google-/Apple-Pay).
Of course the option of paying for the tickets with crypto is nowhere to be found:
According to an article in the german Tagesspiegel, the question wether this "Cash Ban" will stay after the pandemic is over, wasn't answered yet.
Lots of critique and negative comments could already be heard, especially the idea of the elderly passenger, who is always paying in cash and certainly doesn't use any mobile app, aswell as the many persons in tough financial situations, who are living in Berlin and are only able to pay in cash.
No wonder this system is getting called a "plastic barrier" already, by those people who think public transportation should be open for all of the public.