Are the giant 300-500 piece Amazon first-aid kits any good?

They're impressive on paper and cheap per piece, but specialist communities like r/preppers repeatedly warn that piece counts are inflated with low-value items (lots of band-aids, alcohol wipes, cotton swabs) and that medical supplies from unbranded Amazon sellers can be inconsistent in quality. They're reasonable for car, RV, or home base-camp use; they're a poor choice for anything you have to carry on your back.