Will work under certain circumstance. The liquid will form a layer of rubber inside the tire and seal the hole. So, the liquid has to flow across the puncture. So, I would think that the tire needs to roll to ensure all the holes covered. So, hard to say what will happen if the puncture is on side wall of the tire.

If the hole big and loss of air too fast, it is difficult to the tire up to pressure again before the seal works. So, probably need portable pump as well.

No, I never use one but since this is not new and has been on market so long until now; I believe it works like what I imagined above