They’re not just fitted as anti-tamper… there are more sophisticated fasteners to do that.
Basically, they are used because they’re better suited to the assembly process than the old-fashioned Phillips and Pozi-Drive heads we used to have. The screw is less prone to wobble when it’s on the end of the screwdriver (often on a robot) so the chances of crossed threads and misplaced screws are reduced, which of course speeds up assembly times and therefore makes the job more efficient and cost-effective.
They’re also able to be done up to a higher torque than the old-fashioned heads.And on the plus side, easier to remove if they get rusted.