Excalibur rounds are useful because:

1. Each Excalibur round replaces 20 dumb shells. That is to say: it takes 20-dumb shells to do what an Excalibur round does in 1-shot. It takes 60-dumb shells to do what 3-shots can do. It takes 200 dumb shots to do what 10 shells can do. Yes, dumb-shells are more than 20x cheaper than an Excalibur shell, but think about the effects of this...

2. Because of #1, you have grossly simpler logistics: one truck of Excalibur shells (though very expensive) can replace 20-trucks of dumb shells for the same mission-effectiveness. Of course, if the Russians blow up the truck of Excalibur shells, that's a lot of money lost, so there's a bit of "all my eggs in one basket" effect here. But it also means that a few careful trucks of expensive weapons serve as a gross force-multiplier. Its easier to move 1-truck of explosives (and to hide it) than to try and hide 20x trucks of explosives from the enemy.

3. These Excalibur shells are compatible with any M777 or other 155mm platform. So any "dumb" artillery, previously shooting 20km shots, can randomly turn into a 70km guided-artillery beast.

> you should compare Excalibur shells to 9m54x rocket artillery, the second of which is superior in every single domain

You're comparing a cluster-munition against a guided high-explosive shot.

Cluster-munitions do jack-diddly squat against bunkers. A guided high-explosive shell in contrast, will blow up any earth-bunker or maybe even concrete-bunkers.

A salvo of 24 Excalibur shells may completely obliterate even a dug-in concrete bunker position (4-shots from 6 guns battery over the course of 1-minute). A salvo of many 9m544 cluster dumb shots will bounce off the concrete.

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If we're talking about artillery vs artillery, something like the Bofors/Nexter Bonus 155mm round should be used instead. Unguided, the shell flies off in the general direction you shoot.

But the shell then explodes, and inside are two "guns" that are programmed with infrared sensors to shoot explosive-formed-projectiles (with 100mm of penetration).

The Bonus 155mm round automatically scans 30,000+ square meters in the area you aim, and fires two accurate shots with 100mm+ of penetration in that area from the top down.

This demonstrates yet another capability of 155mm NATO guns: they are very flexible. It only takes 10-seconds to load a NATO gun with a different munition. Maybe these guns were firing dumb-rounds 5 minutes ago. But they had a change of plans and are now firing BONUS rounds, or Excalibur rounds.

Rocket-artillery takes many hours to reload. They're just less flexible in the field (despite having a far more devastating opening salvo).

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The "bread and butter" will continue to be dumb-artillery shells. But randomly using these incredibly sophisticated, high-quality shells and mixing them into the battle plans can really be ferocious to fight against.

Its very difficult for the opposing army to plan around enemy gun artillery, if they are able to randomly change their munitions like this.

Lets say Russia's spy satellites or spy-airplanes see a battery (6x guns) of M777 sitting in an area (guarded by S300 anti-air missiles, so bombing / strafing runs aren't worthwhile). What's the plan of attack? Assuming a grounded attack... without knowing what shells that team has, Russia can't really form an effective plan.

Lets say Russia advances with an MLRS system of their own. Well guess what? Ukraine / USA spy satellites or whatever will see that MLRS system advancing, and the M777 can retreat / move away before the MLRS is setup to attack.

M777 guns "mask their intentions". Its very difficult to know what an M777 gun is up to doing, because it has so many different kinds of rounds.