Runes of Magic US / AU

Always keep in mind that Runes Of Magic although allows things like Curse Client, it does not offer support for those clients.
Bad things can happen adding things like those,using htis case as example: a player had not set his app properly and lost everything in his backpack.

Look here.

It is used to collect data for the official database. I have not used it, though it could be pretty useful for filling in some blanks in the database, such as NPC locations and so on. Still, don't really have any idea how it works.

As it is a service provided by the official database, I doubt there is any kind of worry about the safety of the app, and it is unlikely to use many resources, though I don't know as I haven't used it.

Even though it (seems) to be Official, Runes Of Magic does not have any* add-ons and therefore it is not supported.
That is not to say Support will not try and help you even if you use them.