Yeah, I spoke to a friend who's flown DXB-MCT in EK F when it was cheap with EY miles. He said ex DXB it might make some sense (though not much) because you at least get the lounge.
But apparently there are pretty much zero ground services for First Class at KWI or DXB (assuming you don't arrive at a remote stand), and the flight is super short.
In the end, I went with coach.