I'm new to Decentraland, have a few noob questions

Hello I’m new to Decentraland and this is my first week exploring it. I just have a few noob questions.

  1. How long has Decentraland existed? Are there any other video games like this that is a sandbox and uses crypto ingame to the point where I can actually make money playing a video game? (for example, I’m currently farming crafting materials so I can make NFTs and sell them for mana. It might take me a couple months though before I can craft my first NFT

  2. I just finished my first puzzle! (location is: -46,61) At the end of this puzzle, I was supposed to open a chest to claim some kind of a reward. But when I opened the chest, I got an error message saying, “Sorry, there was a problem with our servers. Please try again later”. This is the second time I discovered a chest like this. The first time was when I randomly found one while exploring a pyramid structure and I found one at the top of a flight of stairs and I got the same error message. What kind of reward was I supposed to get? And why didn’t I get my reward? Is there really a point to any of these puzzles besides entertainment purposes?