Sony's Gaikai just for backwards compatibility?

Pretty soon after Sony purchased Gaikai, there have been rumors about the tech being used to provide backwards compatibility with PS3 games, for the upcoming PS4. Now the Wall Street Journal has said they have a source confirming this fact.

I am curious if others think this is really all that Sony plans for the cloud gaming service. The purchase itself was a $380 million dollar expenditure for a company that is bleeding money. Additionally, the build out and maintenance of the servers necessary to run such a service will be a significant investment, and ongoing expense.

So could Sony really be spending that amount of money just to provide backwards compatibility? With this generation, there was talk about PS3's compatibility with PS2 games, and it was a bit of a selling point, but was quickly removed to make the console cheaper. I am having trouble believing that even Sony could justify such a massive expense to provide that one bullet point. I just don't see people really caring that much about this feature. As a PS3 owner, I really don't mind having a PS3 and PS4 hooked up to my TV at the same time for the year or so that I may be playing both systems.

What do you all think the Gaikai purchase could be for?

I am hoping for something that could allow me to purchase a game, and play it locally on my PS4, but that the purchase will come with a Gaikai code, that allows me to also play that game anywhere via Gaikai. Obviously, you would want to play locally when possible, but the thought of being able to have my console games accessible on my computer or tablet or Vita or phone, when I am away from the house, is a pretty cool idea.