> Can you please provide some evidence that this kind of scripted and recitation-heavy instruction is beneficial compared to other approaches?

Singapore/Hong Kong/Japan/Taiwan/Macau dominating the PISA

Singapore's math program in elementary is actually much less recitation and rote based than we are used to in Western mathematics education.

Indeed, it's very much pictorial and intuition-building in ways that fans of DI tend to look down on. It's concept and problem solving before rote.

I don't know so much about these countries in primary education, but I do have a few Japanese textbooks from secondary school translated into English and published by the AMS. This material also seems less rote-heavy than I am used to.

E.g. I'm looking at an on-level grade 7 mathematics textbook, and it's spending a lot of pages justifying the idea of negative numbers in addition and subtraction and with pictorial representation and has comparably few problems to do.

In a US math textbook, this material would have been done before grade 7, but in less depth. There would be a whole lot of rules, algorithms, and rote practice.