I don't see why it would be, to be frank. "Serverless" is a how. It's a tool, not a solution, and you should be expected to pick up new tools without waving around a piece of paper saying you know a tool.

Except for button-pusher roles I've always hired for whys, not hows, and certification programs seem to never care about the whys. College degrees don't assert that you know how to learn, that you know how to derive the whys--but, in my experience, they correlate better than cert-hunting does.