(1) What I feel is missing in the exercise app landscape is a product that is highly-usable to people and spans all types of activity. So my objective is to let people check in with only two clicks regardless of whether they lifted, did a yoga class, went for a walk, or played in a softball game, and ultimately to compile all of that information into a single chart which represents your exercise life. I was really inspired by the simplicity of the Robinhood and Cash App UIs and always wanted to get that "single chart" to work for exercise (it's still very much in the works as I'll mention in #4 below).
(2) There is a lot of high-risk activity on Robinhood, but those use-cases don't negate the fact that it also allows anyone to make recurring deposits into a wide range of asset classes. Maybe we can think of a highly-leveraged trade like someone maxing out their back squat on their first day in the gym and severely injuring themselves. A recurring deposit into an ETF would be more like making sure you do a light jog every day. There will always be various use cases when you make a generic product.
(3) You absolutely fade/atrophy when you don't exercise regularly (in fact, you do so frighteningly quickly)... but the benefits of regular exercise also do compound over time when you are consistent. I don't think we need to dive into whether that compounding maps directly to the S&Ps average annual return or not to agree that if you are able to get yourself to do some push ups every day for 50 days straight, you'll be in a lot better shape than you were to begin with :)
(4) Regarding the science-based approach. I couldn't agree more. We're trying to develop estimates from experts on how effective each exercise is for different adaptations, and we're starting here: https://docs.google.com/spreadsheets/d/10f_PoTkQ0T5wDmrokRh-...
For now, our goal is to see how people enjoy our planning and check in flow / UI. Would love it if you gave the app a shot and continued to share feedback as we build! :)