Some products are only available on Amazon, altough there's always an alternative on another shop.

I try to avoid Amazon because of how many bad products are on their platform. Other shops also list third-party sellers, but by avoiding those platforms and only buying on proper non-marketplace shops the products usually meet a minimum quality. At least my experience with shops that actually specialize in a specific categorie (pc hardware -> mindfactory.de, electronics -> reichelt.de, ...) is generally better.