A rate buydown makes more sense if you plan to refinance or sell within that window, because you capture the lower payment without paying for a permanent price reduction that outlasts your ownership. It also keeps the purchase price higher on paper, which can matter for future comparables in the neighbourhood.
A straight price cut makes more sense if you're staying long term, since a lower purchase price reduces the mortgage balance you're paying semi-annually compounded interest on for the life of the loan, not just for a temporary window.
Run both scenarios against how long you expect to hold the mortgage before deciding which ask makes sense for your offer. Get your hand-reviewed valuation from Joel Dyck.