I can only give you a generalization from one example. I wouldn't buy that, because when my kids are sick, they stay at home, or only go out shortly; so this doesn't solve a problem I would perceive to have.

Also, maybe a better solution already exist, I just didn't do a proper research.

I actually imagine that the hand-powered cleaners could be improved, to make them useful. Either increase the part you compress, or add one-way valves so that you could quickly press it repeatedly. Though at some moment they would become inconveniently big. But I assume the cordless vacuum also is kinda big.

So it's a question of how big and inconvenient device are you willing to buy to solve a problem that happens rarely (that you need to take the sick kids outside for a long walk).