Indeed, that was a large portion of the original idea behind making siacoin inflationary. We want people to use siacoin for storage, not for hoarding or speculating. And, speculating can even destabilize the currency (as we're seeing on Poloniex today). It's not really good for the network to have the price flailing around a lot.
Price flailing is unavoidable while we're in the early phases of growth, but the permanently inflationary aspect of Sia should help eliminate some of the speculation and should encourage using the coin for it's primary purpose - buying storage.