luckily I haven't been working with such companies, I have had enough of my dose of Digitalisierung by interacting with public offices. But at least I can communicate with the Finanzamt via email, after signing a document where I made clear I understand that emails are not a safe communication tool (while random non-certified letters are, apparently).
> while random non-certified letters are, apparently
They kind of are. Somebody would have to go and steal the physical letter and then read/scan it to make any use of it. That excludes pretty much all attacks on the process --- at least such where criminals might hope to make a larger profit than most other criminal enterprises available to them.
Whether that makes the letters a good idea is a different discussion...
