But to the point you do raise - so now I have to keep a tab open in safari constantly for each book I'm reading or might want to read? If I'm going on a trip and want to take half a dozen books because I'm not sure which I will read, now I've got 6 tabs open in safari constantly.
You can close the tabs and re-open any number of books without an Internet connection. The books will work normally.
That is the whole point of offline-first!
Feel free to test it! Bookmark the url and turn off the Internet. Now close the tab, hard refresh or restart your computer if you want to test that far. Reopen your browser and open the bookmarked url and the book will open up on the last page you were on and work normally with full UX/UI without Internet connection.
[0] https://developer.mozilla.org/en-US/docs/Web/API/Service_Wor...