Verify the identity of developers

My point was that as a EU citizen you don't need a *passport* to travel around the EU; your national ID card is sufficient. Only when traveling outside the EU would a passport come into play.

What makes passports semi-feasible for "identity verification" is that there is a true international standard for machine readability (and decoding) of their information. But passports are not a given, meaning you'd realistically need to accept various [sub-]national ID cards in all their infinite diversity, with potentially a separate reading/decoding/verification mechanism required for each issuing agency.