@ultmateragnarok That's why it was logical to be uncharted before the anniversary update. But it's a completely different thing now.
@Archangel-Timmy But their needs to be a logical reason for it being unknown to the common man. If their is no good reason, then it makes no sense.
If the Sea Dogs wanted to challenge and test players skills in the arena then they should invite ships over instead of hiding themselves. And it's such a huge well-lit high place that it's hard to miss anyway. Anyone that sails the seas a few time will locate it unintentionally or even end up there thinking it's a normal outpost. There is no secrecy in the location, it's just not featured on the map.
If finding the location was such a challenge that only a true sea dog can locate it, then why can you get there from your very first Sea of Thieves play session by just starting up the arena mode with zero knowledge of the game? Those first time players can even get inside. It would be strange if they know how to get inside and can compete in the arena, yet "they should not be able to locate it".
DeMarco, son of the pirate lord and the man behind the idea of the arena, is in the lore a greedy pirate that mostly cares about the gold. So it's likely all the shops there earn him some gold. Why would a greedy man hide his shops making it less likely to get sales? The arena mode is likely a huge marketing stunt and gambling place to him. More popularity means more gold, so why would he hide it.
This place has a lot of supply barrels and shops. It's a place very logical for a sailor to visit. So that reason makes no sense either.
I have not found any logical reason to keep it off the map.