It's really based off the opposing offense's scheme. If a team's scheme is based off of speed, a lot of times, they're using that speed to confuse the defense into getting lined up quickly and making the MLB, or whoever is in charge of calling reads on the defense, make the right read within a few seconds. By effectively 'flipping the script' and getting lined up prior to the offense, the defense forces the QB, or whoever is in charge of making the offensive reads, to react. So, in theory, this would put the reactive pressure back on the offense. I would say it would be even more effective if the defense has a few base formations that they can use to disguise different blitzes and pressures. It would be especially effective if that same defense was rotating players constantly, which can be used to disguise special blitzing packages that utilize specific personnel.
I'm no football expert, though... So, I could be, and probably am, wrong.