Liquidity Risk: Paying in full ties up a large amount of capital in one asset, reducing financial flexibility and liquidity.
Opportunity Cost: The capital used for a lump sum payment could potentially yield higher returns if invested elsewhere. Although, at current rates that is probably unlikely.
Leverage: Mortgages allow for leverage, where you can control a large asset with a smaller initial investment.
Interest Rates: With historically low interest rates, financing can be more cost-effective than using cash. This is currently not true.
Diversification: Investing the money in a diversified portfolio can reduce risk compared to putting it all in a single property. See Leverage.
Tax Benefits: Mortgage interest payments can often be tax-deductible, which is not applicable when buying outright.