Something like this, just for the air:
Yes, though because a diver is not a small fast target a rifle with supercavitating bullet would suffice...
It is not super fast but the bullets it fires should reach out quite far and fast... a bit like a remote gun turret that can move slowly around the thing you are defending... port or ship or whatever...
I rather suspect it would be also rather valuable in dealing with mines found in operations... move closer to the target at 1knt and then shoot it.... not the end of the world if you are too close... but perfectly safe for you.
You would make a terrific military engineer hahaha!
I would probably be a terrible engineer, but I like to think I might be a good ideas person...
I guess the Russian solution is intended not only for reusability but also for fast interception. UAVs are small targets than can fly very low and they are probably not that easy to detect from very far away. Maybe there is no time to go hunting them one after the other but rather throw many interceptors
I think we can both agree the wide variety of threats means a variety of solutions is needed... from a Kalashnikov gun that is actually designed to jam as a normal part of its operation...

to this weapon, and many other solutions in between.
The key is cost... you want something cheap and simple that can deal with a lot of targets... preferably with the target not even knowing you are there...
I mean the Serbs used helicopters with door gunners to fly alongside expensive NATO UAVs and just shoot them down with PKMs... brilliant... and relatively simple.
We have seen a requirement for new Helicopter types to be able to shoot down small aerial vehicles... so the Mi-28NM could have airburst 30mm cannon shells which would also be useful...
Exactly what you said
Interesting... they have had what they call cargo rounds for their 30mm cannon for fighters and aircraft where the round travels as a complete projectile until a fixed distance where a rear charge detonates and sends subprojectiles in the direction of the target like a super shotgun blast.
The round itself is optimised for shooting at ground targets like troops or soft targets in the open and is intended for targets 1.8km from the muzzle give or take a metre.
A 40mm grenade could pack a lot of small projectiles with a charge powerful enough to give good range and coverage, and if you had a set fuse to detonate the grenade at a fixed range... 40-80m or so, you could use a laser rangefinder to position your aircraft to fire them so that the blast would cover the area around the target so that even if it stopped or turned or sped up it would still get pummelled...
The issue is that while the 40mm grenade will be more expensive than shotgun shells, it will also deliver a much more powerful blow at greater ranges, so it could deal with all sorts of targets... including enemy helicopters... the key would be forward facing fragmentation effect for the grenades for a good even spread of fragments.
It could be used to stop a swarm of small drones, but it could also be used against an infantry attack on the base too.
A shotgun shell would not have the capacity... a human sized target out to maybe 20m most of the time... further away and you probably wont get enough hits to assure a kill... buckshot would be necessary as lighter loads would probably not hit hard enough to do enough damage on some UAVs...
Fragments from an exploding grenade will be travelling much much fast and do rather more damage...