The foundations principles of marksmanship are a worthwhile study for anyone who intends to use a handgun with precision, regardless of the target. Once those principles are ingrained and committed to the subconscious, the mind is freed for problem solving and the rest takes care of itself.
Precision is, if anything, more important to the defensive shooter for a host of reasons- not the least of which is that peripheral hits with service handguns do not stop anybody in time frames that matter to your survival. They may induce a 'surrender' but a determined adversary will keep on coming until you break their motor mechanisms or punch their CNS. It takes good centerline hits to do both.
I've seen some excellent target shooters make the transition to defensive shooting and I'd damn sure rather have one of those guys backing me, than someone who shoots fast around the edges of an adversary. I for one don't care how many hands they use, as long as they're landing the right kind of hits.