Still comes back to "can you sell enough keys on your own to make up for the amount of sales you get through Steam, even after the 30%?" It's great if you think you have a hot game or product that will be sought after by a large enough audience vs people seeing a game show up in their feed or on sale or a friend is playing it or however it ends up in front of you on Steam, a game that maybe you've never heard of before and now you're going to buy it.