I've been tempted to do that but always assumed I should give prespray dwell time before agitation
On most jobs it's fine to shower feed.
On heavy grease though you should allow dwell time before agitation. This allows the treatment to break the "surface tension" of the soil first (not really the right word but I think it makes my point) which then allows it to break away from the floor it was stuck too more easily.
Otherwise you would need to spend more time scrubbing to eat away layer after layer. It's possible but more time consuming. (This usually is a restaurant type of thing where the grease is too thick)
Again you can always just shower feed, but in some situations it is faster to allow dwell time then agitate