Now that you have send BBP by e-mail, I wonder what it'd take to build a BBP system based on SMS & phone numbers? Android & iOS app could be set up to send payment to contacts (either e-mail or phone number). It would go with the theme of helping the unbanked. SMS support would be even cooler, but I don't know anything about telephony servers or what's involved with SMS, but cointext.io has a limited rollout globally that supports Bitcoin Cash & DASH. I could see BiblePay leveraging IPFS as a smartphone app, but maybe SMS is a more difficult challenge.
I know Twilio has some awesome API & hooks and they can be used globally... there's a cost to using and maintaining the service. $1/mo for phone numbers and a cost for sending/receiving messages. It is a centralized service so I don't know how far such an idea would evolve with BiblePay.