Non-technical people may assume no server infrastructure. From the developer perspective -this is accurate-; the actual hardware is handled by someone else, there is no concept of it that the developer has to work around.
I'm not sure why you'd think someone would believe no software would be needed; even when servers are involved, there is software located elsewhere, on a mobile phone or a web browser or similar. No one is going to say "Oh, serverless? Then I don't need my software development team any more!"