Steem Backed Dollar is simply Steem that is exactly a US Dollar's worth. As Steem Price goes up, the "value" of SBD will definitely go down. So really there isnt any difference so to say.
Maybe perhaps there will be difference due to arbitrage. but for me, it doesnt really matter which token i hold.
Thanks for your explanation but if you go into the real exchange to change them, you may notice the difference
Yes.. that's what i meant.. Because there is a sort of balancing period within the steem blockchain. so it would react as fast as the market does.