Cage shelves

I'm setting up a cage for my new baby boy who's coming in 2 weeks. The 5 level cage has ramps (which I've read that I SHOULD NOT use and will remove immediately) but the shelves or ledges..(what ever you call them) are wire, like the cage. Why am I reading that I should replace these with pine ledges? Can't I just put swaths of fleece or towels on them?



Any help is appreciated greatly!