there is a lot of platforms to add to this game and they are not added lol (PC, Mac, Linux, PS3, PS4, X360, XboxOne, PSVita, Windows Phone, Android, iOS, WiiU, 3DS, Nintendo Switch, Stadia), if the platforms are added the game will be more easy to track.

99% of our runners play on PC, however we do accept other platforms as long as they are on a modern version. We don't see any reason to have a distinction between platforms.

By more easy to track, do you mean easier to find Terraria leaderboard on speedrun com? That may be true.

But it was a conscious decision to stop listing platforms, because if you do, that automatically creates a variable that will appear next to each run. There have been like 5, if not less, submissions in the past half a year that weren't on PC, and they were all on Android. So on most categories, including the front page category, you would just see a variable saying "Platform: PC, PC, PC" on every single one of the runs. That's just bloat. And the only way to avoid it is to not track platforms on the leaderboard. That's SRC for you.
In the rules it does say that you can use platforms other than PC.