Daemons are independent entities and fully sentient. 

They are more or less employees of Apex. Incredibly hostile Daemons are locked  in containment for the safety of others.

Daemons are your Human character's coworkers.

While not all Daemons are sociable. In order to get paired with a Handler they have to at least be able to tolerate that person. They're putting their lives in each others hands. They should be able to respect that.

All Daemons grant Humans a power and are fully capable of manifesting themselves as a separate entity from their vessel and can fully choose to do whatever they want independent of their Handler.

So to answer your questions. 

Handlers are borrowing the power the Daemon's grant to them. So it's not always 'on'. And no Daemon means no power. All the more reason to have s vessel that's easy to carry.

It's essentially a buddy cop thing. Like imagine trying to hide a talking horse from your Landlord sort of thing.