[nugator]

I came across it when studying computer science 20 years ago, yes. Heard about it after that but never directly needed the knowledge.

I'm sure it's used under the hood in a lot of code I write and have written but so is XOR, manual memory management and a bunch of other lower level implementations that I don't need to spend time on when developing on a higher abstraction level.

Not sure why you would expect all programmers to know about binary trees specifically.

[Retra]

Binary trees are the simplest kind of nontrivial tree, and trees are used extensively in programming. Most computer problems are solved using trees of one kind or another.