Memory would indeed be an issue for mixing MPA and SPA, but besides not being an issue for a full SPA it also wouldn't be an issue for sites that are all MPA ex

Memory would indeed be an issue for mixing MPA and SPA, but besides not being an issue for a full SPA it also wouldn't be an issue for sites that are all MPA except AJAX submissions that don't cause a SPA page change. Currently I think an all MPA would waste the localStorage space. SessionStorage by default with prominent placement in the docs would be better I think. It would automatically clean up the data from visitors' disk space at appropriate times, whereas the localStorage setting puts it in a place that gets persisted for quite some time. Thanks for those links, I've read them but it's good for others here to see them.