MRTA/MRTT is insurance for the loan amount, to help pay off the loan in the event of your sudden death or total permanent disablement. This is to prevent bank from pursuing your dependants for loan repayment that they might not be able to repay, which is burdensome for your dependants and risks them losing your house if they're unable to repay the loan.

This is separate from insurance for the house itself, which would be insurance like houseowner/householder insurance, fire insurance, and master fire policy, which are insurance to protect house from damages.

So "shorter than loan period" (or if you insure less than loan amount) carries risk of, if your coverage ends and after that you didn't settle loan, and if you meet an untimely demise or accident/illness that causes you severe disability, you may have issues to repay loan if you do not have a large enough sum of money saved elsewhere that your dependants can access to for loan repayment/settlement.