Players can delete their own messages they've posted in either General chat, Trade or crew chats

Sometimes players accidentally post in the wrong place or sends a private messages so it's public in error. This option allows the player themselves to delete it as soon as they notice the mistake rather than having to highlight the mistake by asking for other players to delete it for them (especially important if the message is of a sensitive nature (ie health related) helping to avoid embarrassment)

It can also mean if a player posts in capitals in error, they can delete it and re-post in lower case to save the several posts that follow where others all comment on capitals having been used and not to use them.

It can also mean that players looking to make a trade can delete their request once the transaction is complete