Where else do you get mortgages?
I mean, technically you can contract a mortgage between any two legally able persons.
But I’d say a mortgage between private individuals is a rare exception.
Usually it is bank/credit unions, or corporations specializing in mortgages as their primary business. But I think you can lump most of those under the umbrella term. At least as far as their employees being able to just approve or deny you for personal reasons.
I think in this case it works well enough.
Most comedy works by subverting expectations. And sometimes you can shift the burden of establishing these expectations to the audience by offering an unclear and vague statement, that later is revealed to be the punchline to the joke.
There is a certain risk involved because how well the joke works on an individual basis is a question of how imaginative or unimaginative the audience is (depending on how the joke is constructed).
A joke that relies on lack of imagination basically turns the audience into their own straight man. While the joke that relies on imagination banks on you being the straight man to the flights of fancy of your audience.