There was a time I did, there was talk of building out use cases for Steem Dollars which could well be an excellent idea given the power of the Steem blockchain.

Then the founders started discussing doing away with them all together and judging by recent comments from @ned he still believes we can live without them. He seems to think SBD's confuse people and it would simplify Steemit if we only had one currency in two forms.

So, if that is the plan moving forward I see little to no benefit in holding them for any long term goal. Of course things can and do change around here often :)