2 words, Occam's Razor, using my deductive powers bestowed upon me by the god that doesn't exist, the player you saw do that is simply an idiot

i'm not sure what you mean by tactical conclusion. but in the simplest terms, he wasted points by doing that(BTW you never mentioned what level he got 'uproot'. i am assuming he didnt get it until a later level if at all). btw as much as i enjoyed replying to you, for future reference you can just google *skill or item* +'demigod' and you should find the official description + special notes, which will always tell you everything you need to know and more. so far in my experience with Demigod, i only noticed 1 skill that acts a tiny bit differently than described, and that is 'Rook's 'power of the tower' in that they disappear after a certain amount of time, which they fail to mention in the description, but i found it here

http://demigod.wikia.com/wiki/Power_of_the_Tower in the 'notes' section

The Demigod Wiki is very good read for stuff like that. I always google Demigod Wiki and whatever you need. In this case Queen. 

In another thread someone said that compost makes no sense at all if you can still get morale as morale gives about the same advantage as compost plus other advantages. So compost is a bad pick overall.