You have probably received a mailing from Catholic Travel Centre which includes an invoice and information about the optional travel insurance they offer. Please do note that while the cost for it ($139) appears on your invoice, it IS optional, and your own decision whether or not to purchase it, AND whether or not to purchase it through Catholic Travel is entirely up to you.
So- the choice is yours. (Most participants in the Italy pilgrimage did buy the optional insurance.)
Travel expert Clark Howard weighs in here.
And here is a video from AAA Travel that helps explain some of the benefits of travel insurance: