I think that link is referring to going for a workout with just the monitor itself to record your heart rate - no other devices present. You can use/build your own mobile or desktop apps without needing their software if that's what you're wondering.
I made a custom iOS app for my wife and I to monitor our workouts using their SDK and I really happy with it
I think you should read 10% Happier by Dan Harris. He's a news anchor that tried meditation after having a panic attack on air. He's doesn't oversell the benefits (he says he feels about 10% happier) and he covers his journey from skeptic to practicing every day
I don't have a CS or engineering degree but I've been working as a developer for over a year. My advice is to have a good portfolio of projects that you can use to showcase what you can do.
I had major imposter syndrome in the beginning but now I'm a key contributor to the product. You learn a ton on the job so it's important to apply for one before you feel completely 'ready'
You absolutely can. I got my first development job at 31 with no experience. Make a good CV with the projects you built and go into an interview demonstrating enthusiasm for solving problems and making software.
If you want a job in front end dev spend time mastering vanilla javascript / es6. Practice using git and do a lot of reading to get a good grasp on the industry.
freeCodeCamp is surprisingly good and teaches you a lot about modern web development
Similarly you can put most vegetables in a glass of water and they'll last a whole lot longer. Where I live vegetables aren't always very fresh and by doing this I can take wilty kale, for example, and make it full and crisp
I made a custom iOS app for my wife and I to monitor our workouts using their SDK and I really happy with it