Suppose you need to share text online quickly, e.g. some code with a password in it. But you don't want just anyone with the link to be able to view it, because of the sensitive information inside. You need access control, and not simply a password prompt because if someone else obtains your message sharing the link-plus-password that gives them access just like obtaining a message sharing a link that lets them in would. A couple of solutions are providing a question-and-answer prompt you know most people couldn't figure out, or even easier sharing it with their Google Account's email address and requiring them to be logged in via that.
In this scenario I've typically used Google Docs. But a Google Doc is quite slow to load, and the process of creating a new one takes a fair few seconds on top of that. https://pastebin.com/ is nice and fast and even has syntax highlighting, but you have to pay to get private (as opposed to unlisted) documents.