As your property increases and what you have paid in repayments also increases then you have a nest egg there in equity that you can borrow to purchase another investment or whatever you choose. Remembering that you need to earn enough to support the new borrowings. Equity borrowing is a great way to build that extra room or garage. Increasing the asset of your home. I would be wary of borrowing against the equity in your home to purchase something that does not increase this value. If borrowing for business then a business loan with its tax advantages makes more sense. However if no tax advantage is gained by borrowing for a car then the usually lower home loan rate of an equity loan might be advantageous.
Another reason for taking out an equity loan or remortgaging is if you around the 55 year old bracket. Lending institutions aren't always too keen to lend money to people who are senior in years as the ability to pay long term is hampered by their age. At 55 years a person still many years of payed work left and is still looked favourably as a borrower. So by remortgaging you can keep a loan open and use the equity or redraw facility for your whole working life. Some people keep this loan small and easily manageable, even if they have their own funds available. A maturing super annuation fund can be used to pay out the loan once retired.