A couple of years ago, I would have concurred. But for some time already you have the possibility to use the e-ID through Postident (https://www.deutschepost.de/de/p/postident/privatkunden/iden...) which is kind of well integrated in many businesses. Moreover you have private / corporate solutions like Verimi (https://verimi.de/) that incorporate functionalities of the e-ID. There is even an alternative (https://www.openecard.org/startseite/) to the official app. (EDIT: The alternative is open-source, but so is the official app. Removed adjective.)

I really like the development that has gone into the e-ID. They even have thought out a safe way to update your PIN (https://www.pin-ruecksetzbrief-bestellen.de/)! The biggest drawback of all is the lack of any marketing, IMHO.