Took the survey. Imagery is typically 400 level marksmanship stuff, but I have no doubt that students (most of whom never get to that level) would be better off if they brought it into play on day one.
FWIW, I use imagery for every shot I take offhand (or dryfire offhand). The sight picture is wobbling quite a bit and it's nice to have a trigger finger that works on it's own once the sight picture you see matches the picture you are visualizing. The only time I'm at risk of shooting a 9 is when that mental image slips or isn't right.
I don't use it for rapidfire or prone. Sight picture is stable enough and/or there's not as much time allowed (due to timer or possibility of shifting wind conditions). I do give it a quick thinking through the course of fire, but it's not the same as the pure sight picture image that I use for offhand.