scientiae: It's a solution to the problem: "Is this (sale) price better than any previous offering?". So, if you see the current price is lower than it has ever been before, the customer can confidently purchase the item knowing that noone else has bought it cheaper.¹

¹ Not considering the variable value of your purchasing currency. For instance, a 2008 US dollar is worth probably two or three 2023 dollars, less the opportunity cost incurred by spending the money a dozen years ago on a game that now you can buy for inflation-ravaged chump change.