Losing the second hand market would be bad as far as I'm concerned. I tend to buy mostly new, but have discovered that you can't take other people's ratings for a game for how much you will like them yourself. I've just finished Assassins Creed Origins and accumulated something silly like 100 hours enjoyable play time! Just tried Resident Evil 2 and found it so bad I deleted it after 10 minutes play, so that will be going on eBay. Both games have 5 star ratings on Amazon and with reviews that make them sound like my sort of game.
It would be annoying to pay full price for a game only available by download and no means to sell it if you don't like it.