The value shows up in two places. Holding the property costs less every month than it would at today's rates, and if the mortgage is portable or assumable subject to a lender's underwriting, a buyer taking it over can inherit that lower payment instead of financing the whole purchase at the current rate.
Not every lender allows assumption, and the buyer still has to qualify under the lender's current underwriting even when the rate carries over, so the benefit is real but conditional rather than automatic.
Whether that low rate should change a decision to sell now versus later depends on the specific mortgage terms and what the house itself is worth. Get your hand-reviewed valuation from Joel Dyck.