I can't say I've noticed any good reasons to rely on it. Didn't reach for `OrderedDict` often back in the day either. I've had more use for actual sorting than for preserving the insertion order.
I don't often care about a specific order, only that I get the same order every time.
Granted, I live and work in TypeScript, where I can't `===` two objects but I could see this deterministic behavior making it easier for a language to compare two objects, especially if equality comparison is dependent on a generated hash.
The other is guaranteed iteration order, if you are reliant on the index-contents relationship of an iterable, but we're talking about Dicts which are keyed, but extending this idea to List, I see this usefulness in some scenarios.
Beyond that, I'm not sure it matters, but I also realize I could simply not have enough imagination at the moment to think of other benefits
But maybe it does all just come down to equality comparisons. Just not always within your own code.