I think it’s good advice for beginners. If you’re inside a VPN you get a little more breathing room to figure out how to properly provision and wire up your services without having do deal with all the security and scaling concerns that can come from public hosting. Also, new hosters are really likely to set up their reverse proxy and not patch it and leave it open to known vulnerabilities that get exploited months or years down the line… not that that ever happened to me…

Anyway, I think inside a VPN is a good way to get your feet wet. Setting up a public website is fun but I wouldn’t advise it as a first step.