There are also reasons outside infosec concerns. For example where such PKs would be directly related to your revenue, such as orders in an e-commerce platform. You wouldn't want competitors to have an estimate of your daily volume, that kind of thing.
> Enter username to play for free directly in your browser
I was so happy after seeing this thinking, "so amazing of them to let me check it out without having to register" only to discover that it led to a register form :(
I love metrics that are essentially irrelevant but sound very cool like "our BETA users have burned two million calories collectively and lifted 500,000 tonnes".
> “End-to-end encryption” sounds nice — but if anyone can get into your phone’s operating system, they will be able to read your messages without having to decrypt them.