Modular laravel - Question about interacting with diff modules

Now i may have goitten the wrong end of the stick.. but i am going through the course and it seems he is just using modules classed directly in a diff module..

what i was expecting is that maybe he would create an event/listener saying 'hey' an order created... then order module might listen to it, create the order.. and then emit 'i have created an order' then Mailr module might sent the email, return the ORder details to the 'web page' module who will display success to the user etc..

the way he has done it, it seems if i was to change/add classes i would have to change the calling code as well and in fact while he was refactoring he did changes in both modules.. wheras if it was event/listner then he wouldnt need to.. a calling module wouldnt need to know whats changed..

The other Q is although the modules were separated, db are still together, i would expect a db per module.. (or maybe thats going too far. ie a microservice?)