It's a five-bedroom, three-bath property, set up as a three-bedroom, two-bath main house with an attached two-bedroom, one-bath apartment. There are lots of houses in this neighborhood with apartments, and it's probably a great way to afford a bit more house than you'd otherwise be able to.
I don't think there was any particular reason I didn't buy a house with a rental apartment when I bought my house. Not sure Dennis asked if it was something I wanted or if it just never came up. It's probably nice not to have to worry about maintaining someone else's home as well as your own, not to mention dealing with finding tenants, chasing rent payments, and so on.
Anyway, if you want a house on a bus route in a great neighborhood with trails nearby, either because you need five bedrooms or because you're happy to rent out an apartment, take a look. I can certainly imagine someone buying the house, living in the smaller apartment, and renting out the big part of the house, too.