People are not numb under it.

However, there are many forms of torture that are not based in pain. The current hot topic in the USA is waterboarding, where you lie the victim head-down on an inclined board and pour water (or more commonly something less pleasant) into their mouth until it fills up to the trachea. Very, very disturbing, but not pain in the usual sense and highly effective. I don't know how the relaxation caused by Versed would affect it, nor do I particularly want to learn.

However, my speculation here is not simply about Versed but other memory blocking drugs. The classified world has almost surely researched other memory blocking drugs, some of which may not be relaxing or anaesthetic. Versed is just a reminder that memory blocking drugs are available.