When I enclose text in a pair of dashes within a post, it gets formatted as strikeout. This is very annoying. It happens to other people, too. I regularly see posts with a long sequence of text struck through, which almost certainly wasn't the poster's intention.
Strikeout can be useful on occasion to convey irony, but IMO it isn't used that often that it justifies a shortcut, when the icon to format a selection of text as strikeout is there in the editor on every post, along with bold and italic.
So I hereby announce that when I persuade Elon Musk to buy Mumsnet and make me CEO, removing this auto-strikeout feature will be my first task on day one. Unless of course my perfectly reasonable request to remove it (i.e., this post) has been met by then. 😀