The problem with the mobility is not the weight, but how large it is (the whole kit). You have the main backpack and another backpack for the controller tied to the main one. The kit is so large that it would create extreme discomfort while carrying it around (not counting the silhouette). Soldiers are already experiencing difficulties while trespassing trough forests, bushes even without the large backpack (sticks, branches like to tangle in ties, straps, MOLLE). A narrower design of the backpack or even better, a hard container mountable on MOLLE as in the Spike Firefly is a far better and comfortable option for carriage.Maybe I'm old, or maybe because of where I was during my time, but if a soldier is having a hard time carrying a drone that weighs less than 10kgs, there is a problem with fitness in the army. Although, I'll admit no idea how much the case itself weighs, so let's call it 15, but my point is, a soldier should be able to carry that as long as necessary, along with their usual load, since they won't give it to the machine gunner or marksman or poor sob who is carrying the rocket or grenade launcher.
And again, you're comparing apples to oranges mate, or rather, comparing Kargu to what it isn't. Grenades have a certain radius that'll kill everyone outright simply because of the blast pressure, outside of that, it's up to the shrapnel to finish to job, or not. A simple 40 mm exploding on the ground next to the target will kill anyone within, damn I can't remember the exact numbers, let's say 5 or 10 meters. Kargu will most likely not have that, or, that radius will be smaller and as you said probably directional, since it has a proximity fuse/sensor.
A modified rpg round, or a mortar round, or a grenade dropped on top of someone or something could have a greater impact I don't disagree with that. I also agree with you that a cheaper alternative to use against terrorists makes a lot of sense, like the one you described. But I still don't believe it is as useless or terrible as you seem to believe, we disagree on that.
Btw, the configuration you showed is actually an RF seeker as far as I know, not an rpg or anything else and I don't know if it has passed beyond testing phase yet, or any of the other warheads.
You probably got me wrong on the warhead of my "cheap drone" dream design. It will not drop the grenade directly, but it will serve in the same way as FPV loitering munition. I am using the Ozok hand grenade as a reference to the design of the warhead that I think could be implemented. Just enlarge it a bit, take out the timed detonator and make it explode on command. Also what I meant by giving the example of the 40mm VOG is that even a small munition (warhead) can inflict heavy damage let alone an enlarged Ozok. By observing combat footages from Ukraine, I concluded that the VOGs are maybe the most effective and also cheap munitions that can be carried by drones so just imagine the damage done by the modified, bigger Ozok that also sends shrapnel at 360o not leaving a chance to run in any direction or hide.
If you ask me why I didn't gave an example with an RPG round, the answer would be that in my vision for the drone it may require higher performance of the platform which will increase weight and my idea is a simple light and cheap drone that still packs great enough damage against infantry and light armor, some endurance and can also be used for recon tasks (20-25 minutes fly time, 2-3km communication range). The design of the modified Ozok in my mind would be a bit fattier in shape than the standard OG-7V round, packs weaker punch (a bit less fragments and explosive), but still comparable. Still, not a bad punch for that kind of drone.
Also, regarding the configuration of Kargu that I posted. As far as I see this is a warhead influenced by a 60mm mortar round and the RF seeker is most probably the part that I encircled in red together with an E/O. Most probably we are talking about a module as Kargu is made in such a way that you can swap warhead and E/O payloads in seconds. Someone correct me if I'm wrong.