No. Because it uses a lot of calcium. It will outcompete your corals (and shell-building inverts) for calcium and gradually starve them to death. If halimeda comes in on live rock as a hitch hiker, you should pull it off.
I'm curious as to why anyone is selling that stuff?
I had some that hitch hiked in when I first got in the hobby. It as a pest and spread prolifically! And I never even added calcium or anything to my system.
Wow I didn't know it used calcium. I have had some in my tank for a long time and have never had any problems. Mine came in on a frag rock and hasn't grown very much since I've had it. Hasn't seemed to bother anything though. I may have to prune it though if it uses that much calcium.