How much is gained by writing about yourself? Aside from personal development aspects, less than video-logging. But likely different information than video-logging. Possibly stuff buried in your childhood. Logging biometrics like heartbeat could be more total benefit than video-logging, but again different information. Having a combination could prove more useful in a synergistic manner than any one information source on its own, because comparing them against each other allows you to infer more information.

The same goes for cryonics. At a guess I'd say preserving the nanostructure of your brain to the highest technologically feasible level is going to be thousands of times more effective than all the digital and plain-english data in the world. But combined they would be significantly more effective, because of the data you can gain by cross-referencing different types of information.