But that's not the argument here. Python type hints allow checking correctness statically, which is what matters for agents.

The best benefit depends on your problem domain.

For a lot of the business world, code flexibility is much more important than speed because speed is bottlenecked not on the architecture but on the humans in the process; your database queries going from two seconds to one second matters little if the human with their squishy eyeballs takes eight seconds to digest and understand the output anyway. But when the business's needs change, you want to change the code supporting them now, and types make it much easier to do that with confidence you aren't breaking some other piece of the problem domain's current solution you weren't thinking about right now (especially if your business is supported by a team of dozens to hundreds of engineers and they each have their own mental model of how it all works).

Besides... Regarding performance, there is a tiny hit to performance in Python for including the types (not very much at all, having more to do with space efficiency than runtime). Not only do most typed languages not suffer performance hindrance from typing, the typing actually enables their compilation-time performance optimizations. A language that knows "this variable is an int and only and int and always an int" doesn't need any runtime checks to confirm that nobody's trying to squash a string in there because the compiler already did that work by verifying every read and write of the variable to ensure the rules are followed. All that type data is tossed out when the final binary gets built.