E.g. sending links to your post to friends and family. Many family members don't have accounts, and some days all they see is a login prompt. Many times, my recipient is on a different device / using a different browser / cleared their cookies because their ISP tech support somehow thinks that helps - some days, all they see is a login prompt, and don't remember their password, and don't want to go searching for it.
All of this has ensured that none of them like Instagram links, and do not want an account.