GnuCash may not support concurrent users, but it does support concurrent programmers as its XML config files can be checked into git. From my programmer perspective, revision-controlled accounting makes sense. You can fix bugs and change names, merge and split accounts, all with history, comments and easy reversion. And unlike with h?ledger, you have a nice GUI for managing most day to day tasks.
Checking the XML data into text-based version control is a really interesting idea. you could probably do something similar with the SQLite data, using a tool like Dolt.