No one benefits from a half-baked half-implemented app, which these kinds almost always are. If they are fully-implemented in maintained, then it's a different story, apps can change lives, but it's hard long work to change a life. But if the app is abandoned or half-done, then really the client will end up viewing the developer more or less like the other scam artists they have to fend off.
In my opinion, the approach itself is pretty flawed. You as a talented person come help those less fortunate than you for 12 weeks, it seems like a win-win, but really I think most sides just end up frustrated. Off the top of my head, a better solution might be to actually try and build your own cleaning business with that community and then see what tools you need. Software is software, cleaning is cleaning, you can't be a domain expert in one and then just know what will work in the other, I think you need deep expertise in both.