Sure, it's unlikely someone will be totally clueless who can talk the ins and outs of a project. Let me put it another way. If we put all the engineers I've managed/lead throughout the years through your interview process, you would probably filter out the one or two who were bad, but you would not always select the strongest engineers. You'd select the strong engineers who were confident, gregarious, and articulate, and leave out the ones who are humble, shy, embarassed by their accents, not used to bragging about themselves or articulating the details of past projects.

Talking about those things is a learned skill just like writing on a whitebaord. Hence why good companeis that do whiteboarding interviews also have traditional rounds. You want to give candidates multiple avenues to shine.