Actors is one of the worst programming models possible. It's hard to observe actor-based systems and debug them. The protocol complexity (and complete protocol informality) usually brings much more trouble than any kind of locking/synchronization.
Observation requires good logging, but this isn’t out of line for any complex system. Debugging (as in actual breakpoints in an IDE or post-mortem analysis) can be facilitated with stack tracking (this same problem occurs with async await patterns and is solved in a similar way).
The advantages and disadvantages exist, but I think it’s an extremely effective programming model for many use cases. Formal state-machine programming, that’s the worst model, unless you need it.
Actors are self defeating because they turn everything into a distributed system.