I mean you would really have to go back to 2015 or 2017 and look at how many people were taking 5 or 7 year arms.

Every mortgage rate in Canada is reevaluated every 5 years. It sucks

When rates were low it really didn't make sense, unless you planned to be paid off before adjustments. If you have poor or average credit an ARM can get you a lower rate and the mortgage will boost your score to refinance to a fixed rate you couldn't get before. ARMs have max adjustments as well, so if you anticipate rates increasing more than that, you can get a lower rate than available at the time and in the future.

Bridge loans are less popular now, so you could get an ARM or interest only ARM on a new house and refinance later after selling your old house.

I got a 10 year ARM back in march as it was 1.125% lower than a 30 year fixed. If I cannot get a good refinance in the first 7 years, I'll just focus on paying it off fully in the next 3. Worse comes to worse, I'm like 95% certain it will be worth at least what I paid for it in 10 years if I did need to sell it for any reason so I'm not worried at all.