Both need City approval before they count as legal, and both are treated differently depending on whether the unit was part of the original build or added afterward. Joel Dyck can explain which category a specific property's suite actually falls into. The 'four types' framework elsewhere usually splits a detached unit, an attached addition, a garage conversion and an internal conversion into separate categories, a distinction that matters more where zoning treats each one differently. Saskatoon's bylaw cares less about which of those four descriptions fits and more about whether the result meets building code and gets a permit.
A garage conversion or an internal basement conversion in Saskatoon is judged the same way as any other secondary suite: egress windows, ceiling height, a separate entrance in many cases, and fire separation, not by which of the four labels it would carry somewhere else.
The category label matters less here than the permit does. Get your hand-reviewed valuation from Joel Dyck.