Would be a pain to setup and increase WU cost more than having it internal if everything HAS to be sent through backend. Also permissions will be harder to manage.
You can setup full security, admin panel, permissions, and all within the same app.
Agree with @chris.williamson1996 here. Was in this position a few months back and contemplated building two different apps to serve two different industries, although the same type of services were being offered.
Ultimately I made a global control panel and two different dashboards and separate datatypes within the same Bubble app which turned out much easier and cheaper than going with two separate apps.