The charging port doubles as an anythingelse port. Excellent for docking stations and one-cord work station setups in office.
The standard already exists and laptops all already have these ports, anything else would be extra, extra space used, extra development, extra parts, extra unique parts, etc.
We want One cord for all devices to be charged, not one for phones, one for PCs, one for TVs, one for laptops, etc.
USB-C is a better form factor for thin devices than anything circular.
We want laptops to be able to charge stuff plugged into them fast, so they already have all the components (or most of the same designs) for "can be charged themselves".
Don't have to manufacture or source a separate power brick, just pick power brick ABC that can handle your wattage desire.