I was excited by the idea of this sensor but I haven’t decided on a “best use” case yet.
Currently, I’m using it in a home safe as a way to ensure if it is ever opened, I’m notified. This function obviously adds to my peace of mind when I’m away from home.
However, what I originally planned on using it for was a dog bell, where my dog could tap it triggering an automation/scene to let me know he needs to go outside. Prior to the p100, I’d been using the T1 vibration sensor attached to a bell the dog paws at and it works great. Unfortunately the p100 was a little too large to use in that same way.
After discovering it would be a little too large for that use case, I toyed with the idea of using it outside as a way to trigger a scene/automation for the pup to let me know when he wants to come back in, but unfortunately because it’s not waterproof, that wasn’t an option. I’m a bit upset as I write this because when reviewing other testers posts on this topic, I’ve run across a few who received the p100 WITH AN OUTDOOR PROTECTIVE CASE, which would have then ALLOWED me to use it in the way I had contemplated after realizing it was too large for the originally intended use case, but such is life I suppose 
What I would really love to see it do, is serve as a pressure sensor for a very specific automation. For about a year now, I’ve been using the T1M ceiling light with various iterations of aqara motion/presence sensors (currently on fp300) but I’ve always wished that while I was in bed, any motion occurring therein would not trigger the lights to come on. The fp2 had too many false triggers that would wake me up, and now the fp300 works for the most part, but I had to position it in a corner where a wall largely blocks its view from my bed (thereby eliminating its effectiveness of sensing other motion on that side of the room, which kinda sucks, but it’s the best I can come up with for now). BUT, if this device served as a pressure sensor, it could be placed under a bed, and when you’re on the bed the pressure could “trigger” it, thereby availing a “condition” to my lights on/off automations. In a perfect world, if they added this feature, I’d jump in bed and lights would stay off and as soon as my feet hit the ground in the morning, the lights would come back on… no one makes such a product but I honestly feel like this is something a ton of people would use…. Idk maybe I’m just crazy lol
Anyways, the p100 (without the protective case) still presents as what appears to be a high quality form factor, much better than previous generations of small switches/button/sensors made by Aqara. If you had a white one on a white door, it’d honestly blend right in, in my opinion. The ability for it to work on the HomeKit was the big reason I wanted it and it did connect to HomeKit right away. However, as others have pointed out, there are a few kinks that could be ironed out presentation wise, as each type of trigger presents in HomeKit as “button 1/2/3 etc.” so unless you’re super techy, like me, or were otherwise told by someone else who already figured it out like me, the average person would likely have a hard time determining what each of the 6 different “buttons” (triggers) actually meant.
Anyways, that’s my two cents on the p100
