I don't expect it'd even be worth $20 to me, but I can sort of understand the online appeal. Sometimes having a relatively basic game happen in a shared open world, where people can choose to cooperate, adds some fun moments. The Division and Sea of Thieves would be examples of that. Watch Dogs 2 also had some very good times where you might be driving around, and without any "prompts" or loading, have a chance to join a midcity chase with/against another player.