The Costco ones are great for everyday cleaning... but you want a thicker/heavier (higher gsm) for your car. Rims, glass.. that's about all I'd use them for on a car.

If you don't care about your car... they are 100% worth the money.

* I also wouldn't use a cheap microfiber cloth on my $6k monitor 😃

If you want to do everything possible to not scratch your car, there are better options.