It's about managing cash flow so you can afford the repayments when they fall due. Some people start out with interest only loans to claim maximum interest.
example from a bank to illustrate (they should update the example to reflect inflation. Rental income - $19,000. Interest expense - $27,000. Other general expenses - $4,000. Pre-tax cash flow (negative) - $12,000. ( $230 each week) to support the property while you wait for your annual tax return refund.
or....Go online through MyGov each year and make a PAYG withholding variation application Once approved, the tax department tells your employer your new tax rate – and your take-home pay effectively increases.
Rental income - $19,000. Interest expense - $27,000. Other general expenses - $4,000. Tax break (deductions) - $9,000. After-tax cash flow (negative) - $3,000. ($57 each week) is easier to manage