Unreliable for moving robots, not locking, easy to snap off the board, PITA to strip USB-C cables, break out the +5V/GND wires to splice to a DC-DC converter (and the breakout boards take much more space than just a proper power jack).

95% of the time I power Pi with DC-DCs, not from a wall source. (But even for a wall source, it's way way way easier to find 5V3A, 5V5A, even 5V10A adapters that give you nice, easy to use +5V/GND terminals or wires than it is to find a USB wall wart that can deliver enough current for the Pi 4.)

In general, I want a power connector for power when integrating the Pi into a larger device.