It depends on the context.. For example, I use an invoicing web app that stores previously created invoices indefinitely in localStorage. This gives me the benefit of not having to manage login credentials and keeping everything client-side. It also gives the site's developers the benefit of not having to manage user accounts or server side state.

Without being able to use localStorage as a long term store, I'll have to register for an account, have to deal with them handling my data, etc. Losing the functionality of localStorage as a long term store has disadvantages.