So that’s where I would say, as long as performance doesn’t matter it’s better to default to B-Tree maps than to hash maps, because the chance of avoiding bugs is more valuable than immeasurable performance benefits (...)

I don't quite follow. What leads you to believe that a B-Tree map implementation would have a lower chance of having a bug when you can simply pick any standard and readily available hash map implementation?

Also, you fail to provide any concrete reasoning for b-tree maps. It's not performance on any of the dictionary operationd, and bugs ain't it as well. What's the selling point that you are seeing?