> Are they buying an option on the right to receive dividends at some indeterminate point in the distant future?

> Do they think they'll receive a fraction of the enterprise value when Google gets bought by a bigger company?

> Will Google get sold off piece by piece and they'll get a pro-rata share of the liquidation proceeds?

Yes, but also a bet on other people's demand for those things - its asset backed. Since they all are based on USD I think they're a little safer bet than a cat fad.