A whole post about hash tables and he doesn't mention the real reason trees are better than hash tables: lower variance!

> Hash tables become full, and bad things happen

The bad thing is not a crazy long probe or even rehashing to enlarge the table—it's that some random individual insert is stuck eating the entire cost of rebuilding the table. For many applications, I'm happy with a slightly higher cost per operation in return for predictable performance.

> Hash functions are slow

Great, another unmentioned footgun - hash functions are hard. For example, the hash function he provides doesn't use a prime number of buckets. Oops, non-uniform input data in combination with unlucky bucket counts can generate high numbers of collisions.

Writing a comparison function to put your data in a tree is pretty stupidproof!