This is the best way to think about it. You're renting the money and choosing to invest it in a house. Of course no one would ever give you half a million in c

This is the best way to think about it. You're renting the money and choosing to invest it in a house. Of course no one would ever give you half a million in cash with a 50k deposit, so even if there was a better place to investment the money (e.g. stocks) you couldn't put it there anyway. A mortgage is probably the only way a common person can get this kind of leverage and invest in any asset class. It's really unlikely you have access to some other capital at a cheaper rate (even though a mortgage at 90% loan to value can be expensive, it's almost always the cheapest form of a "normal" person will get), so it usually makes sense to get one.