Oh, that is even worse! Only big corporations can afford to do this, as this borders on banking services and you need good legal grounding for this type of business.

I should probably clarify that by "impossible" I really meant "does not make business/economic sense". You can do microtransactions with individuals, but if you're spending €2 (rough estimate) per transaction for invoicing, accounting, VAT processing, etc, it no longer makes any sense. Thus "impossible".