With the new KMS updates

If you hadn't noticed, getting hit by attacks kind of disrupts you. Demo spamming (which allows you to avoid getting hit) lets you spam it endlessly during the transform time -and only during that time, yes i know- while corsairs stumble slightly from getting hit.

Think of rapid fire like hurricane. Any BM will tell you that getting hit while using hurricane (while not necessarily annoying) still slows it down a bit. Especially if you're constantly getting hit. Each time you have to go through the start up time of the first hit instead of getting a steady stream of arrows... or bullets in the case of rapid fire.

In case you didn't know, there is no start up time for rapid fire. The bullets constantly fire at the same exact speed no matter what or when. The only thing that has to start up is the animation, and has NOTHING to do with it's attacking speed.