No you don’t need NACA5 with your Atom. I bought an Atom a year or two back along with Neat Iota speakers which I mounted on wall brackets. I had a 5m length of NACA5 to hand, so I used this initially. But it is so stiff, it kept moving the speakers out of position, so I looked around for a more flexible alternative in white or cream (so it was less visible running up the wall) that was not too expensive. I ended up with Chord Sarsen, but there are many alternatives.
Roger