The practical uses for a VPN service are plentiful. Want to access a website that your ISP has blocked? A VPN puts that website just one click away. Want to access the US version of Netflix from the UK? Just set your VPN to a US location and you're there. Want to access porn without your ISP or your business knowing about it? Want to download torrents without being blocked by your ISP? It's easy.
That attitude to the safety and privacy of personal data creates an enormous online security risk. Public Wi-Fi networks, which are ubiquitous and convenient, are unfortunately also highly convenient for attackers looking to compromise your personal information. How do you know, for example, that "starbucks_wifi_real" is actually the Wi-Fi network for the coffee shop? Anyone could have created that network, and they may have done so in order to lure victims into disclosing personal information over it. In fact, a popular security researcher prank is to create a network with the same name as a free, popular service and see how many devices will automatically connect because it appears safe.