Origin automatically adds EA’s Steam games

Any EA games that you’ve purchased through Steam (and other channels) will be added to your Origin account for free.
Users of Origin have been noticing that the likes of Mass Effect, Dragon Age and The Sims have been automatically adding themselves as purchased games to their Origin libraries. This applies to game bought through digital channels, and physical copies.
How exactly does Origin do this? The answer is not known for sure, but likely has something to do with the fact that the old EA accounts have now been turned into Origin accounts – meaning games registered prior to the launch of Origin may have had their activation details carried over.
Whatever the case, it’s nudged me back into blowing the digital dust from The Sims again. If only to trap someone in a toilet for the rest of their short life.
Anyone using Origin regularly? How are you finding the experience?