Why are Red-Black trees so popular?
To quote from the answer to “Traversals from the root in AVL trees and Red Black Trees” question


  For some kinds of binary search trees, including red-black trees but
  not AVL trees, the "fixes" to the tree can fairly easily be predicted
  on the way down and performed during a single top-down pass, making
  the second pass unnecessary. Such insertion algorithms are typically
  implemented with a loop rather than recursion, and often run slightly
  faster in practice than their two-pass counterparts.


So a RedBlack tree insert can be implemented without recursion, on some CPUs recursion is very expensive if you overrun the function call cache  (e.g SPARC due to is use of Register window) 

(I have seen software run over 10 times as fast on the Sparc by removing one function call, that resulted in a often called code path being too deep for the register window.   As you don't know how deep the register window will be on your customer's system, and you don't know how far down the call stack you are in the "hot code path", not using recursion make like more predictable.)

Also not risking running out of stack is a benefit.