In every series of Star Trek (at least that I recall), using the transporters has a trained Starfleet operator performing the transport when ordered. It seems that for the run-of-the-mill transporting people or cargo on and off the ship, this could easily be handled by the ship's computer, at least from TNG era onwards. Instead, there is always a transporter chief who performs the transport operation.
Here is Chief O'Brien, hard at work:
I can understand that under challenging circumstances where there is margin for error, then a trained Starfleet operator may be required to make snap decisions or adjustments, but for the most part, using the transporter seems to be a mundane task. A voice command to the computer would be logical, given that the operator is more or less pushing a button when the command is given.
Given that the operator is going to depend on the computer to actually perform the calculations, Is there any in-universe reason given as to why operating the transporters still requires a transporter chief?