Who decides what a transaction is worth? Value is subjective, and even if you can't think of a reason why someone might be willing to pay a lot to send a transaction that doesn't mean they don't exist.
The user experience is horrendous. You can still do it, if you want to. There will undoubtedly be miners who are willing to include such a non-standard transaction for a fee (or maybe even without). As
always, miners are free to accept whatever (valid) transactions they want. This simply changes the default to something more sane, improving the general user experience.