Was some time ago but working for a detailer that bought and sold through the auto auction showed me the amount of $$ invested in these liners was even at best. Auto carpet is extremely resilient and with the right chemicals can typically be cleaned well in any vehicle, and whatever blemishes there may be most dealers will just take some matching spray paint to it anyways
I have no issues with people buying them and completely get why they do, but when on trade the dollars you may get because of your spotless carpets is minimal at best.