Hi and Welcome. My Name is ***** ***** I look forward to assisting you today with your question.
Unfortunately, that app is designed only for iOS devices i.e iPhone, iPad and iPod. Their company didn't design one for Mac.
It won't work on Mac because Macs have different software. Both iPad and Mac are different platforms. The apps designed for iOS will not work on Mac OS and vice versa.
If you have any questions or would like any additional information, please don't hesitate to ask
There are some alternative decision making apps for Mac.See the following
OmniFocus --> https://www.omnigroup.com/omnifocus
CloverPop --> https://www.cloverpop.com/
Try the trial versions or demo first please.
It is OK. Take your time :)