There is another piece missing. When you take money out of an RRSP under the HBP or LLP, while no tax is payable immediately, tax is payable in later years based on the appropriate formula. While you can avoid paying tat tax by contributing to an RRSP and designating the amount as an RRSP loan repayment, you lose the regular RRSP deduction. The worst situation is the LLP - if you education gives you (a hoped-or) increased income, you pay tax / forgo tax deduction at a higher rate than before.