I think they mentioned new miners are eligible as well. "This Promotion is open to all eligible Binance Pool users who mine BTC during the Promotion Period, including existing and new users", i assume for new users the baseline period hash rate would be counted as 0?
Well, if they do allow new users, then you can try, but based on my experience when mining on the Binance pool, they pay low. I don't know the cause; that's what I experience mining on the Binance pool. That is why I switched back to ViaBTC.
If you think you can earn more by joining their promotion, why not try it since the promotion will run until next month and then switch back to a better pool?