I've always considered the term "schwagg" to be a description of the potency of the weed; just like "mids" or "dank". Sure, some schwagg may be better than other schwagg but it won't be better than mids or dank. So, for example, on a scale from 1-10, it might be like

1-3.5-Schwagg
3.5-7-Mids
7-10- Dank