Ah, I see.

I'm not really qualified to give an answer (as I don't have any background in AI) but I'll try anyway: The strategies which succeed in newcomblike problems are in a certain sense 'virtuous'. By expanding the scope of their concern from the immediate indexical 'self' to the 'world as a whole' they realise that in the long run you do better if you're 'honest', and fulfil your 'obligations'. So a decision theory which can deduce and justify the 'right' choices on such problems is desirable.

UDT reminds me of Kant's categorical imperative "Act only according to that maxim whereby you can at the same time will that it should become a universal law."

I think the way in which moral behaviour gradually emerges out of 'enlightened self-interest' is profoundly relevant to anyone interested in the intersection of ethics and AI.