Paced Email is a great useful and simple tool, it is one of my best purchases on AppSumo.

It's simple and easy to use and really reduces the spam you get in your inbox from signups. It has no learning curve, and it has a simple and clear UX. The service is top notch, I had zero issues with it.

I use Paced Email daily for two important use cases:
1) use aliases to sign up for the trial services, if you don't like the trial - you can turn it off easily
2) Helps you to aggregate email newsletters that you do not necessarily need in your inbox, it makes your inbox calmer