I don't know any more than any other Joe Shmo on what maintenance the coaster needs and why. But I'm smart enough to work out that not one single other ride exists that fits all the categories of this thing once you consider what it is, what it's made of, the location and the fact it sits in a different regulatory framework than anything else out there comparable.
So yeah I put it in a box of 1, because it is in a box of 1.
I'm also smart enough to know it's not good business to keep your star player sitting on the bench, so if the ride has a certain amount of maintenance, it must need it. I fail to see why a comment like "I'm keen to know why", basically implying someone isn't prepared to accept that it's ok until they have been given what they feel is satisfactory information, is warranted.
For me if the park says "This is how much maintenance it needs", which it has by scheduling it, then that's all the information I need. As someone who is no expect in the maintaining of a high speed wooden rollercoaster in Australia in 2023 who am I to question it?
As for rusting... well wood doesn't rust, but it sure does bend, warp and rot, and there is also a hell of a lot of metal holding that whole thing together.