The drone scenario is very different, all you have to do is get close-ish to your target. This is very different than having a stick of c4 sit on your target for months. You have to get them to drone-range, say in the back of a lorry, on a roof somewhere, in a box. Then the programming and or AI can kick in and do the last mile for you, whenever you need. Case in point is the Ukrainian attack on the air fields, they parked a lorry nearby.