Question: Why work jumbled sentence puzzles?
Answer: To help with reading and writing.
As a general rule, our minds are built to notice and remember the meaning of a sentence, not its specific words or form.
For example, if I ask you to put your desks in a horseshoe, you won’t remember later on whether I said:
“Please put your desks in a horseshoe.” or
“I prefer that your desks be arranged in a horseshoe.” or
“Could someone help me put these desks in a horseshoe?”
And so on. Our minds seem to go straight to the gist.
That’s great for holding a conversation or reading a book, but it’s not so great for learning to write academic prose, which has very little in common with everyday speech. To write well, you must pay attention directly to the specific words and grammatical “options” you are using (and not using).
In theory, a jumbled sentence puzzle should force your mind to tune into the specific words — and the specific arrangement of those words — inside some else’s exemplary sentence.
At least, that’s the theory. It makes sense to me.