This isn't without downsides though: As somebody with a niche technical hobby, it is hard for me to order from many suppliers because they understandably don't want to deal with consumer protection laws and thus exclude B2C transactions outright ("Verkauf nur an Gewerbetreibende").
I would be fine with waiving my right to returns but this is not possible on purpose, so my only options are to shop somewhere else (often not possible) or found a company (not possible because it would be Liebhaberei - "Running a company without intent to make profits").
B2B company in the US rarely sell to consumers either and their return policy is very different. Not necessary "no return", but only if damaged, not per spec etc. Since we don't have consumer protection laws here I guess it's based on different company structure and expected revenue. In your case it may also be VAT implications (similar problem here with sales tax).