what are the specs on the expansion cards? looks like usb-c.. why not let order with 0 expansion cards and use a dongle of my choosing?
Even if you only want 4 usbc ports, get 4 usbc modules and don't be a baby about the 4x$9 for passthrough cards that don't even have electronics.
The usbc port inside the module bay is directly soldered to the motherboard. The module and bay serve as an important prophylactic to protect the usbc port from damage.
I would only use the real port inside as a backup when some module breaks or is lost or something.
It IS useful, and IS an explicit selling point (to me anyway) that you have the option to do something like plug a power supply or hub or dongle directly in there instead of it being a proprietary connector, but that doesn't mean do it regularly, especially not if the machine is being used in a portable manner where you're always plugging and unplugging.