To me, this is about features. The S9 loses out to the E1DA in my book, so if I'm looking for a really clean DAC that runs as a dongle, I'm going with that.
But running without bus power is a feature that bumps you up into a higher category. If your use scenarios don't make you think of a battery-powered device as a feature, then yeah. There's no reason except maybe the 4.4mm jack for you to consider this thing. Oh, and the somewhat higher power.
The real direct competitor of this thing is the Topping NX4, which will probably be superseded in the next few months, as it's a little long in the tooth. And I guess the iFi Hip Dac, for people who don't believe in measurements, or who need truckloads of power. I think it's got both those beat for now, although I'm probably going to see what Topping comes up with.