Hey, breathing exercises do seem to have quite a positive effect, and are very low cost and low risk - recent meta-analysis here [0]. One of the reasons the evidence base is so patchy, is that compliance is generally quite low, which is one of the reasons for making a digital platform that can map any benefit to how frequently patients use the platform.
The wellness version only creates an anonymised token to track installs - no other data is shared. The medical device version will be a separate app.
Having done plenty of yoga in my life, I can tell you that breathing exercises are not "bunk."
edit: Having any medical-adjacent app collect any data for the use of advertising (according to the app page) seems really wrong.