Agreed. But in the case of WiiM you just might get both.
Right now, the advantages of properly integrated subwoofers for pure stereo are underestimated, because with traditionally HiFi equipment this task has been a PITA. From my very own and very personal experience I can only invite everyone to listen to a pair of cheap fullrange speakers like Dayton Audio RS100-4 augmented by whatever cheap subwoofer with highpass and lowpass filtering handled by the amplifier. You'll be astonished by how far such a lowly combo can take you.
If you already own a pair of speakers covering bass duties pretty well, the advantage might not be that obvious and some progress might be more easily achieved. But I'm very happy that the Ultra will bring improvements in both areas to a lot of consumers.