One of those apps was Lumosity, and I installed it. The first step was setting up an account. I promptly uninstalled the app, and to this day, I have no idea whether it is any good.

It felt odd to me that for a game with no multiplayer component would require me to sign up for an account, and I'm not interested in leaderboards or cloud based backup either. I have the same feeling about email clients, especially when Thunderbird exists and is mostly decent.

Giving up an email account for a free "app" (and not a service) continues to feel odd to me. It almost feels wrong to call it "free", especially since it is unclear to me how my email is used.