Something I noticed in recent years when I found an alternative method to deal with other medical problems - is that most others who were attempting what I was doing- failed to keep a journal or take notes of any kind. With cancer, I cannot imagine not doing this as insights come more easily over time when you have notes to cross reference.
Tracking relevant events, actions and effects is likely to make a difference in wellness and more so in recovery. An app like this one might make journal entries more likely for some people so I support it.