On public WiFi I just vpn into my home network. The issue with public WiFi is that it can be sniffed by anyone in range since there is generally no encryption.

Although pretty much everything we do is over tls these days, and DoH helps protect against even dns sniffing. There's still at least some risk to working in the clear over a public WiFi network. At least in information gathering, what bank you use, etc.

But, there's no real benefit in using a paid vpn over one you own unless you're downloading illegal content, want to watch another Netflix region, or are in a country with heavy Internet monitoring/filtering.