Imagine how much damage 1000 teams of drone operators can do along the front line, a couple of guys in a half ton are more mobile than artillery that can't be everywhere and can cover places they can't, even if they don't have the range. Likewise mortar teams are best employed around Bakhmut and other such target rich environments. However, these things can harass the enemy and cost them lots of equipment all along the front line while stressing out the troops. If they had the targets in range a team could destroy a dozen pieces of equipment from tanks to trucks for the cost of a $10 or $20K bomber drone or even a $3K Mavic adapted for use in war. The main point is, that while not as effective as military hardware, it costs a fraction of it and is in plentiful supply. One drone on a successful mission can destroy millions of dollars' worth of equipment and at night it can fly many missions and bigger drones dropping mortar rounds can drop several per sortie. As long as they have no effective EW defense, then they are vulnerable and there is a lot of front line for EW to cover.