As much as I agree with you and as much as I'm displeased with people having trouble selling things they worked on for months for over 0.99$ I would never be able to live if I had to pay 50$ for every little piece of software I use. 50$ is a LOT for a todo app.

Imagine a world where you had to pay 50$ for every app on your phone (I personally have 10-15 that I use regularly), every web app that you use (these guys have bills to pay too) and everything installed on your desktop computer. You wouldn't be able to use as much as you use today.

The fact is, this app seems great, I might try it, but I usually shell out 50$ for software on either an exceptional game that I know I will be playing for a long time (often multiplayer) or some development tool/license (for example Apple dev program). Organizing my life into items that I can tick doesn't seem that complicated or essential to me that it's worth 50$.