If you are going to make this sort of claim, which the people you are trying to convince clearly disagree with, you should automatically include at least one example.

Ah, I thought the mention of the sunk costs fallacy or the casino were sufficient as examples.

If I'm at a casino in front of a blackjack table, I first make the decision whether or not to sit down, then if I do how much to bet, then I see my cards, then I choose my response. I don't see how UDT adds value when it comes to making any of those decisions, and it seems detrimental when making the last one (I don't need to be thinking about what I drew in other universes).

For the problems where it does add value- dealing with paradoxes where you need to not betray people because that's higher payoff than betraying them- it seems like an overly complex solution to a simple problem (care about your reputation). Essentially, it sounds to me a lot like "Odin made physics"- it sounds like a rationalization that adds complexity without adding value.

UDT does not propagate ignorance. Instead of using evidence to build knowledge of a single universe, it uses that evidence to identify what effects a decision has, possibly in multiple universes.

What's the difference between this and "thinking ahead"? The only difference I see is it also suggests that you think behind, which puts you at risk for the sunk costs fallacy. In a few edge cases, that's beneficial- the Omega paradoxes are designed to reward sunk cost thinking. But in real life, that sort of thinking is fallacious. If someone offers to sell you a lottery ticket, and you know that ticket is not a winner, you should not buy it on the hopes that they would have offered you the same choice if the ticket was a winner.