Why not intercoms??

My thoughts on that is that intercoms usually require a "phonebook" of sorts, so as to distribute the message to the correct zone or individual receiver.

It would also make sense that considering they were in a great room, some kind of foyer perhaps, I couldn't tell. That you'd expect a main through route like that to have an intercom on the wall in that room. Considering they likely would have scanned the room and did not see one. The level of investigative detail set out implies that we're there one there, they'd have found and declared it.

If there wasn't one in a room like that, it suggests that this facility doesn't have old school style intercoms. "Stuck in an era before hey Siri, and ok Google" coupled with the "cybernetic hostess" indicates to me that this is futuristic based time. And as such, you'd expect with the progression of technology that intercoms in themselves would be unnecessary as, thiago found out, it was a voice command device, able to perform a variety of functions, if it can open doors and turn on lights, you'd expect it to be able to send and receive voice like an intercom aswell.

Making intercoms themselves redundant. Which is why the multifunctional device, is not solely an intercom, but it wouldn't surprise me if it did infact have that function.