That free Wi-Fi network may not be so free if it is unsecured and someone hijacks your data. Your phone’s cellular data connection offers more protection.
Q. How secure is my LTE internet connection when I’m connected to my mobile provider, compared with Wi-Fi?
A. On a typical 4G LTE network connection, your data is encrypted and your identity is authenticated and protected. Wi-Fi networks, on the other hand, can vary widely when it comes to security. It’s possible to connect to an open public network where anyone who knows where to look can intercept your information, or you can be on a password-protected wireless network with high-level encryption and other protective measures. It just depends on the Wi-Fi network.