As soon as you played it I got worried. A 50% chance is one I’ll take almost every time. In an earlier game with Marto I built my Tech 2 and had a 40% shot to draw a hasted Tech 2 unit (1 card draw, 4 out of 10 possible cards were hasted Tech 2s). I didn’t think twice about it. I also didn’t draw a Tech 2. It changed the complexion of the game, but the point is at 50%, I’m there.
I do have a question. I’ve considered hasting a building before (specifically the sanatorium). I haven’t done so because the hasting abilities/spells that I’ve run across all seem to mention Hero or Unit specifically, and I figured a Building was not technically a Unit. If it is, does that make upgrades and attachments units as well?