Plastic always continues to give off any VOC in it as it heats, just like rubber. What that means is that any crack fixed will probably just have another one as its' friend later. I've seen wheels with 3-4 cracks in them, as the plastic shrinks it has a tendency to try to even stress all along the length of it.
You can get out much cheaper than the kit by simply using epoxy yourself, sanding it smooth and then repainting wheel with epoxy paint to lessen wear on it. Don't be surprised if the epoxy (yours or the stuff used in the kit) cracks loose later itself, the two materials are different and cannot be expected to stay joined forever, heat will tell the tale there. The joint will last longer if you can rough up the plastic edge a bit for some tooth so the epoxy holds better, say using a thin nail file or something similar.
I personally loathe 'kits' of stuff, preferring to research and then buy only the basics needed, you usually save at least 50% doing that.