I hear that whole life is significantly more expensive than term, so the savings from term could be put aside to later pay for the higher premiums?

Yes. In fact, that's exactly what the insurance company does with your premiums when you buy whole life. Except they take a bunch out for themselves. There's no good reason to buy whole life when you just could buy term and invest the difference until you have enough saved to pay for the cryofund. Except if you don't think you will be disciplined enough to regularly invest the difference, and even then, you can have money automatically taken from a bank account into your cryonics account.