Einschreiben bei der Post! Ihre Vorteile: Sie müssen an den Schalter!

WTF is the service for, if the very thing that makes you use it, is only available at the postal office.

(Not to mention their drive to automate literally every „service“).

Because it’s Prepaid. You’re paying for the option to drop it anywhere or at the counter – but the stamp itself can’t magically record a handover. If you want proof of posting, the human at the counter has to scan it. Makes sense, even if the UX is dumb.