With the new update discontinuing the purchase of daily quest potions using credits, it makes DEC more in demand. We all know the law on supply and demand and we all know they are burning DEC which makes the circulating supply lesser. So I don't see any reason for DEC not to go up in value. While it is still very affordable at the moment, it is the best time to accumulate as much as you can. Plus, it gives you more SPS. So you have to ways of earning just by loading up on DEC. First is the potential of the price of DEC to grow and second, is earning more SPS.
I hate to see it, but what the heck, DEC to the MOON!! XD