When people say sandpaper perches are bad, they're talking about the slip-on sandpaper covers that you put on top of a regular dowel perch. Dowel perches in general aren't great for your bird's feet because they're the same shape everywhere, so the same areas of your bird's feet always press against them. When you put sandpaper on top of them it makes it worse, especially if this is the only type of perch available to the bird.
The concrete perch in the picture looks like it has an uneven shape, and there are some other types of perches in the cage. The bird has a variety of surfaces to stand on so it isn't likely to be a problem. Perches made of natural branches are great for your bird's feet because the shape varies a lot, and you can make your own with a few simple tools and a little bit of hardware. Here's an article on making natural-branch perches:
http://www.mdvaden.com/bird_perches.shtmland a view of the mesquite branch perches I made for my aviary. I got the branches from a tree in my yard. It's a nice bird-safe wood.