I wish I could like this idea, but their price is pretty steep for how small of an area they cover. Their ROI page is all about the cost of growing your own veggies vs. store-bought, but that misses the mark(et). Bots like this do not compete with stores, they compete with your own manual labor to DIY. And the labor to grow some veggies (especially in a raised garden box) is not that painful.
They would be better served focusing on this as an accessibility device, allowing people to garden who do not have the physical capability to otherwise do so.
Drones are fun, but there might be no need to fight weeds so much. They help plants get stronger and kill off weak ones. Farms are overrun with pests and weeds because ecosystem is incomplete and natural cycles are not followed. Some type of permaculture approach like Fukuoka farming could be a more robust alternative to zapping.
They would be better served focusing on this as an accessibility device, allowing people to garden who do not have the physical capability to otherwise do so.