I am not going to hire an accountant from Vietnam to do my taxes even if I would be able to pay him $1 instead of $100. Accountant from Vietnam is not going to learn US or some EU country tax code if he has customers in Vietnam. In case something goes wrong, like you would have to go to court to settle things, good luck on getting someone from other side of globe to the court and setting things straight.
Local regulations, local language plays huge role in a lot of jobs that can be done remotely. But they will be done 'local' remotely so you still compete locally not globally.