Eli5 VPN: https://dnsleaktest.com/ Visit this site unsecured and it will display your general geographic location (county/region). Connect to your VPN and try again incognito and under most circumstances it will display the VPN location instead.

Example scenario: you are in Canada and connect to Netflix and are incredibly disappointed with the Canadian selection. You connect toa VPN from New York a few miles away and you get access to the full United States catalogue. (Netflix is fighting this)

Example 2: you setup your smart vacuum on your home network and being concerned about security, you disabled access outside your home. You can connect to a personal VPN you configure to "spoof" being inside the house while on vacation to modify your vacuum settings.

Vpns are also commonly used as "public transit" for users to obfuscate their identity.

Benefit: When you make a request against a website, they often put trackers on you including your operating system, browser application, and store data like your geographic location. Advertisers are tracking your history, sites are using cookies to charge more with dynamic pricing when you revisit, data brokers are selling that data. There have been use cased where whistle blowers are identified off that purchased data from known journalist meetings. There's a lot of reasons to have a VPN, but never use a free one. Adding an extra jump to your VPN location is definitely adding latency, if you don't need one, it's just extra weight.