When you see the Surveil mechanic on a blue card, you know it goes into your Dimir deck. The mechanic is just too strong to ignore, and the 3/4 flier is something you would play anyway.
Watcher in the Mist is actually very much reminiscent of Cloudreader Sphinx from Dominaria that saw play in almost every blue deck. The effect was too powerful to ignore, and so is the Watcher in the Mist -- just pick it up every time you see it in your Draft.
