I've been doing that for two decades. Most of the spam comes directly to my primary gmail. Because I shared that with friends and family. And at least some of my friends and family shared their entire contact list with the wrong app at least once.
This article however is talking about publishing your email address on a public website. It matches my experience, that simple javascript concatenation stops 100% of spam. Not that I would or ever did trust my primary email address to that.