Bitcoins are a bit confusing

Hey steemians! I've been doing some researching about bitcoins and the way it works, how it works and why it is profitable. Still in this day, i got a not-well sustained understanding for not saying "I dont have a clue" about it. I dont know if im a slow learner, but the more i research, the more complex seems to get.

Hope you guys can help out and answer some of these questions at least!

1.- Why is it profitable? How come that, at least in this comunity, by writing down posts you are getting some income from it? Are you actually producing something? How do you get money of it?

2.- Why is it getting more popular day after day? Besides the fact that you get money out of it, Why it seems to be the "money of future" according with several posts in here? Why this system seems to be the future of our money? Are banks related to this fact?

3.-What exactly means "cryptocurrency" in a simplified way (if possible)?

4.-Whats "mining btc" all about? Why does it exists ad whats its function within cryptocurrencies?

5.- Last but not least, why are there multiple types of cryptocurrencies and why are some of them more valuable than others?

Thank you for your time and your help!