Well if people at Asus forums says it works then you should be ok.
Usbc has multiple purposes + being capable of transmitting video depending on laptop. Because Usbc is multi purpose, it's not always optioned for video. It's different to mini Displayport but they are compatible. Mini Displayport is the same as normal Displayport with just a smaller end and this connection is for video only. If your laptop allows video via usbc then it should work at 144Hz.