More water in their bowls in comparison to for example European ones, the reason is that those types of toilets use different flashing systems and an American one needs more water to flush ,effectively in many countries especially in Asia most bathrooms have bedet which are used for after toilet cleaning and tourists don’t understand why Americans wouldn’t adopt those too after all if you step in mud you’ll go and wash your foot instead of just wiping it off with a tissue the same logic work works here also it reduces toilet paper usage ,so it’s more sustainable and it’s environmentally friendly .
Some say there’s a strong stigma in America around Beday that is extremely hard to overcome, others say that toilets in the US don’t have enough room to install a bedet .So they don’t have those especially if there are other well-known ways.