The wired controller is USB-A. The bluetooth controllers "are" USB-C... but came with A-to-C cables, not C-to-C.
Approximately every time I want to plug something in to my laptop that's not a charging cable for another device, it's USB-A.
More to the point, anything I'd want to plug in to a gaming machine, is usb a.
Most new gaming mice and keyboards sold in 2026 use USB A. Not to mention all the older ones that still work.
In 2026 the single most useful port to add to my Macs would be USB-A, with no close competition. On any device with 2+ USB-C ports, it'd easily be worth sacrificing a USB-C to get a USB-A.
Most devices have a cable that’s fully replaceable so you can choose to use C to C or C to A but basically everything has usb C on the device end.
Yes, but we're talking about the ports on the Steam Machine, so the host end is what matters. And gaming peripherals are likely even more skewed towards USB A, because Macs are not the main target for that.