Sims 3 download digital code use how?

I have a question regarding these sims 3 codes. Since the games are not exactly cheap, I see more and more that these are a lot cheaper than "code". Why are they so much cheaper and how do I use the code? Because it doesn't have much to do with origin itself, does it? They also cost a lot of money on origin. So what do I do with these codes and can I still use them on a new laptop if my current one is broken? How does it all work? Please help, thank you! (I have attached an example from ebay)

You activate the codes on origin

On Steam there are Sims for 5 euro, don't be stingy about the few cents, unfortunately the developers don't get much of the money with the codes…