I would say that, in HomeAssistant, the more “proper” way to do it is to watch entities for state changes and trigger that way.

Events are really only accessible in case you want to manage your own entity, or if you are doing something complex and it makes more sense to publish an event of your own and then trigger from that.

Triggering via entity state transitions (which, yes, under the hood operates on Events) are meant to be a universal abstraction from whatever might be firing over the event queues. Unless you need Events for some reason, IMHO keep it simple.