so ... it depends
the answer seems to be (as I being an attorney am pretty used to): it depends.
In my personal expectation of a defense scenario there won't be time or opportunity for cover or movement. But, if either of the two will be there, I'll be glad to use it.
Still, I think that an unskilled attacker needs more time to aim with his gun than a well trained shooter needs to both pull and hit at short distances (<15m/yds).
Have a nice sunday afternoon!
Si vis pacem - para bellum
If you want peace - prepare for war