Interest-only lending has been traditionally very popular with Australian residential property investors. Several years ago, when lenders offered interest-only lending as an option with no rate penalties, investors would naturally flock towards these structures. Why wouldn't you? It gave you extra cash flow so you could keep investing.
Unfortunately, APRA has since intervened and forced lenders to change their treatment of interest-only loans. This has changed the attractiveness of interest-only lending to the point where it may simply not be worth it any more.