Play via Gaikai for free, but with ads? That's the only scenario this would make sense indeed.
Probably more for short format games. You can complete a few rounds quickly, watch ads and continue.
It's less suitable for an experiential game like Journey, The Last Guardian, FF and Uncharted. I guess they can break at the chapters, but it's going to be really annoying.
People are already used to free casual games (with tiny ads), and freemium games. User experience-wise, getting interrupted by ads is a (huge) step backwards.