From their privacy policy:
The personal information we collect may include:
Name User name Email address Gender Birthday (month/year) Ethnicity Relationship Status Number of Family Members/Children/Children under 13 Experience with Meditation User generated content We may collect other information that does not reveal your specific identity, such as:
IP Address or other unique device identifier Information collected through cookies, pixel tags or other technologies App usage data Geo-location information User generated content Device generated data
Looking at it optimistically, they don't sell or share with data brokers/advertisers, you can block the offensive connections with a firewall, and the app doesn't ask for any information that is particularly sensitive.
Additionally, they use data people choose to share to improve the scientific understanding of meditation and mindfulness. I am someone that values privacy, but I don't find it egregious to use this app.