That's not what he said. We're talking about static websites. Crawling a static website doesn't generate cache on the server, if it does, then it's not a static site, because... it dynamically generates that cache upon HTTP(s) access.

I understood what he's saying in the only way it could make sense for a static site (he crawls a remote site to prepopulate local cache where he locally fills-in the gaps with his static site generator and reuploads), which also didn't make sense.

If we have suddenly stopped talking about static sites, and we're just discussing trivial cache warm-up on dynamic sites, then WTF we're talking about at all?