I don't get why I would choose a dataclass in cases where I've already decided that an ordinary tuple would be a better fit than a normal class (i.e. "anywhere you're tempted to use a namedtuple")

To me, namedtuples are a convenience to give a nicer syntax than ordinary tuples in scenarios where I don't want the overhead of having to store a copy of all the keys with every object, like a dict would. Dataclass seems to be even more stuff on top of a class which is effectively even more stuff on top of a dict, but all the use cases of namedtuples are those where you want much less stuff than an ordinary class has. And I don't want to have to define a custom class just as I often don't define a custom namedtuple in my code but use the one the database driver generates based on the query, which is a very common use case for namedtuples as efficient temporary storage of data that then gets processed to something else.