Straight to the question, What information is the most important to learn about cryptocurrency related topics and that are vital to earn?
What information? Err, the basics at least? On how bitcoin works and how to protect your funds and stuff. I always suggest this link when people ask where to start:
https://www.coindesk.com/information/ | I think it has enough content for a beginner.
I'm also curious, Why do people want bitcoin/ethereum so badly?
Because bitcoin and ethereum are the #1 and #2 cryptocurrencies by market cap; and simply because they're some of the few cryptocurrencies that are actually usable right now.