plus it's tax advantagedI've never really liked that reasoning. Let's assume that someone is in the 30% tax bracket (paying 30% on all qualified income). Let's say this person makes $100,000/yr. They pay $30,000/yr in taxes.
Let's say they also have a $100,000 mortgage at 5% APY. They're paying $5,000/yr in interest. That interest is deducted from their income of $100,000 leaving $95,000 taxable income. Assuming they didn't move down a bracket, they're paying $28,500/yr instead of $30,000/yr, saving them $1500/yr in taxes. Remember though that they're paying $5,000 in interest. It doesn't make financial sense in that respect.
They are paying $3500 more per year than if they paid off their mortgage.
It's seems like a way for people to live in nicer houses (or have more of them) and get a "deal" or "discount" on taxes, though in the end they are paying more.
This doesn't take into account housing prices, cash flow issues, or alternative investments. The rational I've seen in people who could pay off their houses but decide not to is either:
A: I can use this as leverage and sell later when the price is higher, making me money (risky, if the market drops)
B: I can use the money that I could use to pay off my mortgage to invest in other things (also risky, given the nature of any investments)
or C: It's a tax deduction (which from my math doesn't make sense. Maybe someone can show me a situation where the math works out better by keeping the mortgage)