The problem is that you aren't just depending on future improvements in revival technology, you're depending on the current state of today's preservation technology (at the point you die).
And today's preservation technology doesn't have a lot of evidence suggesting that it can work to successfully preserve a kidney, much less a brain.
>In the summer of 2005, where he was a keynote speaker at the annual Society for Cryobiology meeting, Fahy announced that Twenty-First Century Medicine had successfully cryopreserved a rabbit kidney at -130°C by vitrification and transplanted it into a rabbit after rewarming, with subsequent long-term life support by the vitrified-rewarmed kidney as the sole kidney. This research breakthrough was later published in the peer-reviewed journal Organogenesis.[0]
http://www.livescience.com/32175-can-frogs-survive-being-fro...
When the other option is straight ol' Death, I'm not losing much by playing the long game on science coming through at sophisticated cellular repair mechanisms/protocols. I'm definitely ahead of people getting buried or cremated.