In the short term I agree with you. But there are some reasons to be concerned long term I think. One is that if SBD is floating high this doesn't have a directly positive effect on the value of Steem, the main token and that which investors have mainly invested in previously, by design (or at least what they were told about the design).
Another is that why have two tokens if they are free to rise and fall in value? This just complicates the interface and the trading supported on the Steem chain. It's like having two Bitcoin tokens within Bitcoin (though not exactly, approximately).
There are others too.