Steinberg have gradually allowed more of their range to use the soft eLicenser. In particular Absolute 4 and HALion 6 licences can be stored on a soft eLicenser - older versions of these products required a USB eLicenser. I think (and sd1989’s link suggests) that Groove Agent 5 is the first version of Groove Agent where the licence can be stored on a soft eLicenser; I’m not sure, as my licence to use the full version of Groove Agent 5 is my Absolute 4 licence.
Licenses for the latest version of Nuendo, Cubase Pro, Cubase Artist and WaveLab Pro must be stored in a USB eLicenser. There may well be other Steinberg products that require a USB eLicenser - if so, the online store alerts you to the need for a USB eLicenser. Even if you intend to buy elsewhere, you can always add the item you intend to buy to an online store basket to see if you are prompted about the need for a USB eLicenser.