[TheLoneWolfling]

I am well aware of the potential advantages of such operations. And the difficulties associated with trying to use them well and identify when they can be an advantage.

However, just because something is useful does not preclude it from being esoteric.

In particular, there are an astounding number of such miscellaneous and less-often-used instructions in x86 and extensions, and trying to remember which ones exist, and which ones have which limitations, is... a fair feat. Hence, esoteric. Understood only by a few with special knowledge or interest.