Local storage allows developers to store and retrieve data in the browser. The data stored in local storage will not expire. This means the data will persist even if the tab or the browser window is closed https://www.section.io/engineering-education/how-to-use-localstorage-with-javascript/#:~:text=Local%20storage%20allows%20developers%20to,the%20browser%20window%20is%20closed.
Personally Identifiable Information (PII), authentication tokens, user locations and API keys, etc., should never be stored in the local storage. https://www.horangi.com/blog/misuse-of-local-storage#:~:text=Given%20the%20potential%20vectors%20where,stored%20in%20the%20local%20storage.
localStorage can store only strings. Even if you need to store an integer you need to convert it into a string and have to store it. https://javascript.plainenglish.io/storing-different-datatypes-in-localstorage-in-js-ee7f4c5318ff#:~:text=Literally%2C%20localStorage%20can%20store%20only,and%20have%20to%20store%20it.