To be fair if Snyder and the writers actually removed a lot of useless fat and wrote a better script they wouldn't need an ultimate cut. BvS is a mess either way.
Well, yeah. But the Ultimate Edition gave Clark an arc that didn't exist, both he and Lois are shown actually investigating/reporting unlike the theatrical cut where it's more Lois asking for things from Perry and Perry yelling at Clark. Also, Clark, you know, reacting to the bombing.
It also tinkered a bit with Lex's, who is a hot mess and unsalvageable, and yet, he's far more effective
as a villain in the Ultimate Edition because his whole scheme is laid out before us as the others put the pieces together rather than him giving a two sentence summary to Clark on top of LexCorp Tower.
Some of the scenes are also better placed and despite being longer the whole thing is better paced out. BvS Theatrical jumps all over the place, so does Suicide Squad. Feels chopped up and put back together with only a basic outline to checkmark all the scenes, fuck any texture.
Also, the Ultimate Edition has the Alfred chopping wood scene and it's perfectly placed.
And the Arkham "joke" getting trimmed is just silly.