I'm renting for 6 days out of ANC and I tried these two methods. I am <25...

via Hertz US,
Gold Family CDP + free day promo code
I get about $440 incl taxes and fees

via Priceline.com.sg,
I get about $480 incl taxes and fees and LDW too!
I put in PC 144314 which I hope will still work to waive the <25 fee, but right now I don't know for sure

In theory I am covered by my VISA's auto rental CDW, but if anything does happen (tree branches, rocks hitting windscreen, whatever) I am imagining that it'll be much more hassle to go thru VISA then to go thru Hertz's own LDW?

Is there a catch somewhere, since I'm only paying $40 more for Hertz's LDW for the entire rental, while they normally offer it at ~$30/day?