There are 2 compounds here for study purposes. The Vu_BinaryRecursionSearchIndex is for anyone who wishes to dissect and see how the MCG BinaryRecursion operator is wired up.
I've also included my poorman's version of BinarySearchIndex...using a While loop, I actually think this poorman version is less convoluted than the BinaryRecursion one.
I'm quite certain that like Sort, it works only with Ints and Floats, ie. numbers that you can compare...other types like Mesh for example, you simply cannot DIRECTLY connect it to a BinaryRecursion node in the same way you cannot directly connect a Mesh to a Sort node..it can only sort Ints/Floats...sorting a Mesh does not make any sense...