While it might be beneficial in some cases to save the DOM to disk (mostly because of reboots but also, yes, because of people opening hundreds of tabs), I doub

While it might be beneficial in some cases to save the DOM to disk (mostly because of reboots but also, yes, because of people opening hundreds of tabs), I doubt the API would make much difference - sane browsers would still keep any single page either on disk or in memory; they aren't that big.