I once heard a story from a casino moderator on a telegram group. Apparently a user complained about not receiving his withdrawal. After investigation, they discovered that the user had connected to a public hotspot. A compromised public hotspot, that is, and a malware bot automatically changed the withdrawal address. The user thought the casino had scammed him, but the casino had evidence of sending the money to the exact address the user entered.
I do not believe this or what that happened is so different from the angle that you people saw it from. Public WiFi disadvantage is that anything you are using it to do is not private but public, the people that provide you the public WiFi will easily know what you are doing online on your device. In short the person will be able to know the websites that you are visiting. It will not affect the security of your device but it will affect your privacy.
connecting to a public wifi definitely compromises privacy and security
when you connect to a public wifi there might be a server that pops up asking you to allow connection or install something and without thinking much of it, you agree
the “public wifi” you are connecting to might not actually be legitimate from the start serving you fake login pages and once they’re in your device a malware can get installed that may
hijack your
clipboard clipboard hijack is similar to keylogging, it’s possible the person OP’s talking about copied and pasted his address but did not check each character allowing for the attackers to change some details subtly