The problem with Chill Touch it that it's, finally, what it says on the can. A melee spell attack with a range of Touch. And a Warlock being able to survive in melee is a whole can of worms, where a lot of people swear they're too squishy and need something like a Fighter dip for Heavy armor.
Now, Chill Touch with an Eldritch Knight Fighter? Who can easily go for a melee build and substitute the cantrip into an Attack action? That I can see. But Warlocks aren't the best for running up and slapping people in the face.