White board interviews are common across all kinds of companies in SV not just for SW roles. I was asked to invert a tree for a HW test role at Google and very recently asked to come up with code for a particular situation for a test role at Apple.
Oh god, I could not invert a tree in a whiteboard for my life. I took a MOOC algorithm class for fun, but never applied any of it at work and never intended too. The nearer I've ever got was FPGA implementation of some sorting algs, all just for fun.