Edit: By bus powered it could also mean “no power brick required” or something.
Yeah that makes sense. Looking at the listing, this one requires external power.
You are probably better off getting usb-c to dial hdmi instead for that (or just give the mst hub external power).
I tried out a USB-C → Dual HDMI adapter but it didn’t work unfortunately. It only detected another monitor when plugged into the port I use for charging, and when I tried extending my display it didn’t work.
I’ve currently got a USB hub with hdmi ports. I’d like to replace it though as the fan is very loud.