There's *a lot* of stuff on the written that's not in the lab. Asking a couple of verbal questions about stuff candidates supposedly know from the written (but won't be tested on in the lab) seems worthwhile to me.
Also, it ensures that folks who have the highest-level Cisco certification (the PhD of networking) can coherently discuss their trade. At least when I took the CCIE, the first job offered after I passed was in Cisco's TAC - I would hate to call up a newly-minted CCIE there who *couldn't* answer verbal questions about the test material.