And in the end they mentioned:
Get $5 for every new referral
TOTAL CREDITS: $0
After your 3rd referral, we’ll give you $5 in credits for every new person you refer (up to $50)!
These credits are for awesome features coming soon. Don't worry, what you're using now will always be free.
Which means more features on the roadmap will eventually be paid and based on referral/paid addons!