You sound like one of those devs who shunned Dropbox because it's just a simple internet backed up folder you could implement with rsync and some python.
The world isn't that simple and if these "simple rules" turn out to be too complex to easily reason about we as a society will just ignore them.
Yes, this could have some complicated implications for compliance with that law. This is why big banks employ thousands of people in their compliance departments. If you're in country [x] and you're transferring money, you have to follow laws on transferring money in country [x].
Now yes, if compliance is hard, observed compliance may be low. This affects many laws on the books, and if it becomes a problem for regulators, they may take further action to improve enforcement, as they did with capital gains on crypto transactions at exchanges.
This has nothing to do with rsync/dropbox.