Why did Stripe charge me more for a foreign card?

Stripe adds a surcharge for international cards and for currency conversion. In the US it is +1.5% and +1%, on top of 2.9% + 30 cents.

• UK: 3.15% + 20p for international cards, and +2% if currency conversion is needed.
• Canada: +0.8% for international cards and +2% for conversion.
• UAE: +1% for international cards and +1% for conversion.
• Singapore: +0.5% for international cards and +2% for conversion.