Prime pantry is a scam to squeeze $6 more out of Prime members for items that should have free shipping. It's an "enhanced" version of "add-on item" which Amazon first used to circumvent Prime members getting small/cheap items with free 2-day shipping.
As far as Amazon shopping goes, Amazon keeps diluting the value of Prime. Granted when it comes to content (books/video/music) they added stuff to Prime all the time, if you only use Prime for the shopping benefits it's irrelevant.
I will never understand Amazon's terrible business strategy of bundling completely unrelated services together.
Prime bundles free shipping, a music/video service, and photo storage.
Amazon Fire, a (terrible) phone that comes with a year of free shipping.
As a customer, when Amazon first bundled "free' video streaming to Prime, and then raised the price, I felt like I was scammed.
Same about the Fire phone. Instead of offering "free year of Prime", just lower the price.
Why bundle something completely unrelated which raises the price?