Well, you would rarely see it in a written form, though sadly some people do write that way, but a written form is the only way that we are able to introduce common dialect to you.... And we NEVER require users to write this.
Please notice which lesson/skill this is part of. And I do not agree with your NEVER. You see a lot of weird stuff in text messages and chats. The text above is just a literal transcription of spoken Common Czech and that is a normal dialect.