There has been a lot of referral scam on ByteBall, actually the person who sends the payment, get the referral rewards. So some people set scripts to send these payments automatically to the new registered wallets. This thing has stolen many many referrals rewards from many of us.

Knowing this situation, ByteBall has cut off this step of sending payment. Now, you don't need to pay to complete your registration. About referrals, other person has to join through link.
Here is the official announcement. https://medium.com/byteball/byteball-steem-attestations-now-referral-by-link-only-8ec6c79276b5