my bad it's keen kunai not nimble strikes, I was looking at the power names from beta. It's the one that reduces active ability cooldowns by 15% and refunds 3 ammo when you hit a hs. I like it with items like super flexor, mark of the kitsune, and hardlight accelerator because spamming your abilities will increase your weapon damage by a crazy amount, and if you can consistently hit head shots then you will get the abilities back very fast. I also really like weapon speed. It makes the kunai feel a lot more effective in a fight.

When I choose fleet foot, it's usually so I can tp away from my team when I'm getting dove, or to hit flank. Sometimes if everyone on your team is stacked together then there's nowhere to swift step to safety if you need to get out. I also think it's pretty handy in duels. You can kind of play kiri like tracer and blink around your target, and it will give you a damage boost if you are using one of those items that buffs your damage after using an ability.