Is this necessary for the all skills achievement?

You can use this to jump over quite the number of attacks, like Owl's firecracker attack for example.

In my experience this thing's damage is pretty underwhelming. It's your best friend against lightning, but for any other scenario you'll get more milage out of Dragon Flash, EMD, or One Mind. It's not a bad skill, but it's a bit too overspecialized for how much of a ***** it is to unlock. Inner geni gave me almost as much trouble as the old man with the glock.

If you want to use this to redirect lightning, do note that you need to get rid of that habbit of jumping when you see a lightning attack, since the air version of this doesn't elevate you

I dont care if this makes me look like even more of a weeb than i already am but it looks sick and im never going to unequip it

For Sakura Dance, there is a method where you can land a 4th sword strike after taking lightning strike from Isshin/ Genichiro. You'll just have to figure out how.

Submitting myself to being dunked on by Inner Genichiro was well worth it. This thing is amazing. The best part is that you jump so high that using it negates most of the dangers in this game, lmao. It’s like a free get out of jail card, but with damage. And style, a lot of it.

This move will make any fight with a boss/enemy that uses Lightning very easy, as using it means instant lightning reversal, which shaves off a quarter or so of the enemy's vitality. THIS INCLUDES INNER ISSHIN/SAINT ISSHIN, so make sure you have it in NG+ playthroughs. Tested it on inner Isshin, the first phase was easiest, the second phase was the hardest and most brutal but with this move, in the third phase it was all a matter of pushing him to do the lightning attack and he went down quickly after that.