I’m not familiar with how they work or what kinds of data they track and return.
Uh, they track menstrual cycles. So unless you have a thing that runs on a roughly 21-35 day cycle, there’s not much dual use to get from a period tracking app.
Are you trying to think of an alternative use for when cops try to use the app data to prosecute a woman when she miscarries? There are probably some plants that need to be watered ~monthly. Like a cactus or succulent.
I tend to get headaches more frequently at a certain point in my ~monthly cycle, not at the same time I have my period. It’s nice to know it’s coming so I can plan accordingly. Like avoid being on a road trip at that time, or proactively knocking it out with meds before it even starts.
Some people find their cycles affect their energy and recovery a lot, so they adjust their workout plans accordingly. Like knowing when within a cycle estrogen and testosterone are at their peak, versus progesterone.
Aside from just day count between periods, some people track temp, consistency of vaginal fluid, mood, weight, and probably other things depending on their needs.