No military gains in blowing up a status palace.
I’d imagine Putin wouldn’t like it very much, attacking his shit directly seems to me to be a valid use of weaponry. It’s about time the little despot had some skin in the game.
Plus it is surrounded by air defense.
So why not test that defense with a few drones? If it’s well defended then no great loss. If it isn’t then Putin will have to take defenses away from other places.
Remember the bombing of the bridge over the Kerch Strait? Similar-ish situation in that it was a big blow to one of his personal projects. I don’t remember any retaliation linked to that though.