I don't think it's a logical fallacy at all. I mean, anyone who changes their mind about cryonics because of the promise of future Margaret Atwood is probably not being very rational, but formally there's nothing wrong with that reasoning.

I'm an Atwood-reading robot. I exist only to read every Margaret Atwood novel. I expect to outlive her, so the future holds nothing of value to me. No need for cryonics. Oh but what's this? A secret Atwood novel to be released in 2114? Sign me up! I'll go back to suicidal apathy after I've read the 2114 novel.