It is very windy where it is intended for use and as said anything that reduces the presence of mines is a plus. Sure there are more metered, sophisticated ways to do this; but I doubt there are the means and motivation (from those with the means, not the wider population) to apply these.
He says it’s about $1200 to clear a single unit, his design is just above $50 and is capable of clearing more than one. It’s not as if it’s going to run out of power; once it’s out there it will continue to tumble around so the lifespan of one is pretty long. If it’s lifespan is shortened from use it has achieved it’s objective.
You could put a tracking device in them if you really wanted too, but the really practical solution is for the countries which placed these to remove them and for people to stop being d***s to one another. Neither of these are going to happen, he has found a cheap and realistic way to help the problem.
I don’t think this is being demonstrated as a replacement to current mine clearing technology, more a much needed addition.