He was picked two years ago fwiw.
I wanted to have one sinker/submarine pitcher for groundballs and a different look but most of the pure sinker pitchers I know offhand are too hittable and some aren't really bullpen guys. I considered one other submarine pitcher who's a bigger name but he's a pure pitch to contact guy who was a tad inconsistent in his career. Cishek's K/9 rate is also unexpectedly high for a submariner.
I thought the Assenmacher pick (among others) was more off the board personally. OTOH Romo a round or so ago was a great pick, I'd have picked him over most of the bullpen guys that went immediately before him.