HPS is non transferable from property to property, unlike private insurance. Also, if you contract a critical illness your premium will be waived. Most importantly, if you do make a claim (death, permanent physical/mental disability or terminal illness), HPS will only exempt you from paying for your remaining mortgage loan, while private insurance will pay you a lump sum of cash. After paying off the remaining mortgage loan you will have a sum of money for your other expenditure.
HPS premium can be paid through CPF while private insurance is by cash.