Not hard. And is an option as a fall back mode. Especially if not making any money yet.... But not one I would recommend. As you would spend too much of your t

Not hard. And is an option as a fall back mode. Especially if not making any money yet.... But not one I would recommend. As you would spend too much of your time on your payment solution than your business. Continually trying to detect fraud, recovering from devastating fraud that has already happened, dealing with volumes of chargebacks, hiring a lot of customer service people, wasting time on edge cases, accepting customers from different countries, dealign with legal from different countries etc. If only a niche business for local customers, with low volume, then fine. Not for nationwide, definitely not for international, and not for big volumes.