(Wikipedia) Totalitarianism is a form of government and a political system that prohibits all opposition parties, outlaws individual and group opposition to the state and its claims, and exercises an extremely high if not complete degree of control and regulation over public and private life. It is regarded as the most extreme and complete form of authoritarianism.
Why is that a good thing? It would only be good if the results of the decisions were good. Making bad decisions fast would make things worse.
Decision speed is simply neutral unless there is an associated bias towards good or bad results from those decisions.
Because, all other things being equal, getting where you want to go, quicker, is generally considered to be a good thing.
So that would only be ‘good’ from the point of view of your totalitarian ruler themselves. It doesn’t say anything about whether it is good or bad for anyone else. And - critically - only good even for them as long as your ruler was actually competent enough to get to where they wanted to get to in the most efficient way. If they were not going to be taking opposing views into account they would have to be universal experts.
What if they realised they’d made a very stupid decision and if there’d been some more checks and balances that decision could have been avoided?
The Third Reich, I think we can all agree was totalitarian. Hitler wanted to plunge into a war on two fronts against the USSR drunk on victory against France and expecting to beat Britain. Most of his military advisors weren’t keen. But being a Dictator he could just do it and hey presto war against Stalin. As time went on he got more erratic, made more random millitary decisions overruling his generals and made a pigs ear of things but whatever decision he made on a whim happened straight away anyway.
That’s just a famous and obvious example of a totalitarian leader rushing into things and getting where he wanted to go faster which didn’t end well for the leader.