to now where competition like the E30, SK mk2 and other AK4493 solutions exist, yes, price doesn't match performance.
But do these other offerings really perform better, and if so, in a meaningful way? I don't think so.
They do however offer a lot more features, a nicer case and a less cumbersome power supply.
they believe external power has its advantages.
True, on the E30 using a USB power supply vs USB hub makes a small (measurable) difference of something like 2dB SINAD as was shown in that thread.
But the thing is, that a USB charger is small, whereas the transformer of the Atom is a hefty thing, heavy and so large that it blocks the two outlets right next to it also (of the European style at least). I could barely fit it in the cable tray of my desk and see that it could be problematic in some instances.
It needs to be so large since a transformer operating at mains frequency needs to be much larger than the one operating at very high frequencies in a switching power supply with the same power rating.
I suspect they do that to ensure consistent performance since that makes it impossible for the user to use a sub standard power supply (or in case of an amp, to overload the PC USB outputs). But then again, in case of the E30, even a noisy USB power supply doesn't seem to hurt it too much.