I would say the primary.... Qualifying for a mortgage in Canada is extremely difficult. The stress test is certainly in place for a reason. It has protected borrowers, especially from the high interest rate increases we saw in the postpandemic period. It actually prevented people from losing their homes, so it is a valuable measure.
When qualifying for a home, you have to have the income that matches the pricing of a home. This is often an impediment, but at the same time, the stress test has protected many borrowers who would have potentially lost their home if they hadn't been able to manage the price increases.