When every serious Interface has it and the Helix doesnt, then it's not one of them. ;-)
Seriously, why is it important if it counts as 'serious interface'? I think nobody is buying (or even considering) one mainly for this purpose. It's a great guitar effect unit that can also be used for recording guitar (and to some degree vocals or other sources). If one is looking for an allrounder interface for recording arbitrary audio, midi, other digital signals, ... (= a serious interface) there are more fitting products - and that doesnt take away anything off the Helix.
(e.g. I like the light of the Helix's display and footswitches but would never buy it as a 'serious ambient light device')
:-)
Simon268