With the difference that PostIdent actually makes sense. You need to go to an offical PostIdent desk and show up in person with your ID. (or in the new world, aka the internet, it can be done via a live chat for some providers).

While providing a photograph with the ID next to a face can be submitted by anybody how has said photo. If somehow, the photo of HTB send to Lufthansa gets leaked and someone else can use it to prove he is HTB... that is absurd. That is the whole point of PostIdent, it is not just a document check on a dead document (like photo or signed scanned document) but a live conversation with the person to be identified.

Actually, this is where a system like remote authentication with the chip on the ID card would be useful. But as all things digital in German administration, they suck at implementing it. So far, I could use the chip on ID system just once, to apply for a police background check certification from the federal police. I bought a card reader for it and then when you fire it up, it shows what offical services it can be used for... close to nothing useful. Just a handful of insurance companies and very very few Government services. If you e.g. look at Sweden and the BankID authentication system which can be used basically everywhere to securely remote identify yourself to service providers, telecommunication companies, banks, government services or ... well... anything, than you see how it should be done.