Why? It has a more clear meaning than just 'understand', and a 'huh' response should be a pretty good filter for an unsuitable candidate.
People who use grok properly in conversation move up a rung on my opinion-o-ladder.
While the term is firmly established within the jargon (and with good reason, it's a good word to have in the jargon), I have enough distaste for much of Heinlein's work that I don't generally use the term.
I'd have to find some other way to climb your opinion ladder ;)
"to drink"
Wait, not knowing what "grok" means is a "pretty good" filter for a person who is unsuitable for a role as software engineer?
OP referred to a Heinlein quote in his article. I figured that makes using 'grok' in a comment OK.