Just chiming in to say OP’s analysis on Sam is not accurate at all.
The Detonation Charge is meant to be used with proper micro. To say “things die before the charge go off” is just callous. That’s like saying Nova’s nuke is not necessary because things die from Griffin strike before the Nuke hits.
Silly statement right? If I said that, then people will undoubtedly be wondering “why are you nuking and carpet bombing at the same time?” Well, you wouldn’t (not usually), much like when a player cast Detonation Charge on a unit and attacking the same unit - aka you shouldn’t.