I suspect a metal noter would make more noise as it touched the frets. As for steel strings cutting the brass, in theory it could, but not in one lifetime. I have used a brass slide on guitars for a couple of decades. I made it from a brass pipe nipple, with the ends cut off. I also have one made of a bone from a deer leg. It's softer than the brass one. Eventually, they bone would be cut, I suppose, but you turn it to a new place and keep playing. The meat didn't last near as long as the bone has, and it's still going strong.
For slide guitar, the slide is really used as a movable fret, letting you play a note wherever you place the slide, even if there is no fret there. You ideally want a fairly high action for slide playing, to stay away from the frets. The sound of the slide hitting the frets is not music. Look at a steel guitar some time, the nut is 1/4" or more above the fret board. It can't be played with bare fingers at all, with the exception of playing harmonics.
As Ken said, each material sounds different. I like thick glass best, but I dropped it a few times over the years, and it was no more. It had a crack from cutting it off the wine bottle, but it was the floor that really did it in. Steel works, but it rusts, stainless is better, but thin wall tubing lacks something in sound quality, I prefer thicker. The bone sounds good, but I think it needs to be thicker, too. A cow leg bone might be worth trying. I may have to steal a soup bone before Mrs. Wanda cooks it! There are also ceramic slides, but I never tried them. The brass one is fairly thick, and sounds better than the stainless one I have.