@anon52464727 has the ultimate answer in their post. The only thing I’d add is that often people view privacy tools as all or nothing. By that I mean viewing it as either the tool is a cloaking device from everything or it’s useless.
You may want to hide your traffic from a local network but not care that the end point knows who you are. For instance if you’re traveling in a country known to target people like you with malware, having a VPN on while you’re there could make you more difficult to target.
Say I was in a foreign country that may try to infect my phone with malware. If they see I’m connected to my bank website they could send a social engineering SMS pretending to be my bank that says “we see you logged in from an unusual location, click this link to validate it’s you” where that link is a one-click mercenary spyware payload.
Having a VPN enabled would prevent that avenue of targeting.