Thank you for this article, which very well sums up what I did not know when I was new (which is less than 2 months ago....).
Although it might be a little bit off topic, but one should maybe also mention that it is another great safety measure to power up and store Steam Power. As this is not transferrable, it also cannot be stolen. Somebody who stole your active key would first have to power down to get the money - and this could be easily detected by you.