I think the part that is unsustainable is giving points for rent, for people whose buildings aren’t part of the Bilt Alliance (I’m assuming Bilt gets some upside from the buildings in the Alliance). Someone putting $3,000 per month in rent is getting 36,000 points a year, for which Bilt is getting no interchange whatsoever for those charges.
But then some portion of those people will choose to make a minimum payment and therefore begin to incur finance charges on their rent. That's good money for Bilt.