Makes perfect sense when you recall the the Dniper River has been the border between Moskovite and Ukraine forces. Blowing the dam prevents Ukraine from crossing the river to advance.
I agree. The river upstream will be impassable due to decades of silt buildup which will now be an impassable barrier of mud. Downstream is flooded with towns and roads ruined for the foreseeable future.
And this gives the Russians cover both militarily and in their own media for having their troops retreat from Kherson and to have them staff the new defenses in Crimea.
Assuming Russia did this (because it was under their control) it’s a sound strategic decision. It holds off any Ukrainian advance in the direction of Crimea for at least another month.
But it also prevents Russia from advancing west, which in the northern part has been the case for months.