In the Netherlands, when businesses ask for such a thing, you are allowed to black out many non-required parts of the scan (this includes the photo), as well as paste a large watermark over the image. The watermark would contain the date and state the purpose of the scanned ID, to prevent re-use for anything else, if it were to be misplaced somehow.

I'm not sure how that works in Germany but I would sooner send a too-much-redacted scan and have them refuse and ask to see more of it, than send an actual complete scan of my ID to anyone but the government that issued it.

Not that governments are so good at not accidentally misplacing data. But it reduces the surface, at least.