Interest is the price of risk. When a lender holds security over a property, its potential loss if you default is far smaller, and that shows up directly in the rate you are offered. The National Credit Act also prescribes maximum interest rates per category of credit, and secured, mortgage-backed agreements sit in a lower band than unsecured personal loans. Even a difference of a few percentage points adds up to serious money over a multi-year term.
The second advantage is time. Property-backed loans are commonly repaid over several years rather than months, which brings the monthly instalment down to a level your budget can absorb. Just remember that a longer term also means interest runs for longer — so compare offers on the total cost of credit, not the instalment alone. That total includes the initiation fee, the monthly service fee and any credit life insurance the lender requires, all of which must be disclosed in your quotation before you accept.