I've used it on a brand new qtr saw/rift sawn white oak floor.
BUT not by itself.
I bought 24Grit paper for the Planex, Sapphir. As stated above, it will not flatten the floor. I'd imagine with the 24 Grit, and the suction turned all the way up, it "could" flatten the flooring, but it would literally takes days to do it. I know, cuz i attempted this, without a raking light. I thought "wow, looks great!", then i threw down a raking light, was almost like the sander did jack crap.
Not all is lost though.
What I ended up doing is, on my hands and knees, flattening the flooring with a Rotex 150 on geared mode with 24grit paper. I've had Festool for years and it was literally the first time I used one (bought it cuz of this floor project). Wow, what a beast. I got the "Oh Sh17!" handle (495188), which let me use it with all my weight on it. Took me about 2 hours to flatten the floor in a sunroom, hallway, Bedroom with a decent sized closet. I'm also 42 years old. It wasn't too bad, was a good workout.
After flattening with the Rotex and 24 grit, i moved to the Planex, with the extra pad (205418), suction and speed at full, and worked my way up to 100 grit (36, 60, 80, 100). Worked awesome after the Rotex flattening. It was especially enjoyable after having just flattened while down on my hands and knees, so maybe my mood being able to stand and just move it around was biased? lol
To note; This was with the newer Planex (Random Orbit). I have the original Planex, which I used for flattening down variation between sections of subfloor, as I care less about that machine now.