It would cause a domino effect.

First of all, the numbers of Steemit monthly active users are around 150K. Binance has added well over that number of new accounts in a single day.

Listing SBD on Binance will introduce SBD to a huge investor base. That will increase the price of SBD.

• Higher SBD price will incentivize people to join Steemit so that they can invest and earn SBD
• SBD on Binance will incentivize people of other languages to join Steemit as Binance will be the only major exchange that supports many languages and they can now sell their SBD earnings at a fair market price with low fees.
• New money moving into Steemit from the SBD/Binance listing will boost the Steemit economy
• The value of Steemit system will grow exponentially with the number of active users
• Since there is very little logistics like employees, buildings, sales, shipping, materials, etc., the price of STEEM will mirror value of Steemit

In short - the price of STEEM and SBD will go up.