> Even people who can easily afford a 15 year loan will choose a 30 year because the 0.5-1% interest rate is lower than the expected returns of something like stocks, so it makes sense to stay leveraged. There are also tax benefits to paying interest (but not principal) on loans, but these are way less important since the trump tax reforms.

On the other hand, it probably reduces risk to take the 15 year loan if you can afford the payments, in order to more aggressively build home equity and shield yourself from a sudden shock/downturn. If rates shoot up after, say, 5 years (and home values drop 20%), someone who's made 5 years of payments on a 30 year loan will be way underwater, whereas someone who's made 5 years of payments on a 15 year loan still has positive equity.