Yes it is crazy, I have some stats on the mortgage books and they are great buys even if nothing done at all with them, a truly passive investment, as far from rent rolls as you can get.
At 2 times they are a steal
Mate of mine just bought a new rent roll to add to current business, cost was $1.3m and westpac funded the whole lot by re valuing his current rent roll, total Lvr 60ish