I di a similar thing, started paying down in 2007 though, when my mortgage was at 5%.
Canada mortgages are different. No mortgage interest deduction. Fixed terms , so every few years you get a new rate. With the prospect of an increased rate in 3 years the guy is hedging against increasing rates. it's pretty likely rates will be rising someday, he doesn't have a choice in 2-3 years but to get a higher rate loan. If it comes in at 6% is it smart then?
Next, in Canada our houses are worth a lot more, rentals are riskier. My 900 sq. ft bungalow is valued at $300K, rent would be about $1900/month (it can be converted to have a basement suite, bonus). Most people here wouldn't jump on that. I know I could buy Vegas properties, seems risky to buy out of country (I'm not familiar with the rules or the market). Basically I'm not keen on rentals, given the property valuations.