The point is that sometimes the tempo strategy will not work but instead a grind starts, which "Rug / Burg" usually has trouble to win. It's rarely about exiling cards, but about getting some "tempo" by forcing them to deal with your walker or you will create an immense board advantage pretty fast. That's the theory behind it at least. I haven't got to play with it yet...
The example with Veteran Explorer was weird though. If they don't have it on turn 1... arrogant as I am I think they are dead by then. Ashiok would seal the deal pretty fast though, and being able to snatch their creatures sounds sweet. Exiling is also quite strong against them. If they nutdraw us then Ashiok probably sucks, but so do all cards of our deck then...

