There's a few games that use it. In the case of Daytona USA CCE(and Duke Nukem 3D and Saturn Bomberman) it was used as part of some code that detected whether the Netlink Modem was plugged in. Then depending on whether it was or not, it would either directly run the game or run a mini version of the planetweb browser where the user could choose whether they wanted to play a multiplayer game, etc.
