Of course it is! Better to not check the box and not get any sales?
Sure you make less but the odds are that you will get a sale of 30, 50, 100 or more books all at once from someone through Amazon.
You get 40% of the royalties from this. Less cost of printing the book.
You can only check the box for Expanded Distribution if you did NOT check the low content box. Low content books are no longer eligible for Expanded Distribution.
To see all the detalls on Expanded Distribution from KDP website click the link.