I came across this thread searching for information about insufflating jwh-018 (imagine that!) and just wanted to enter my .02 USD.
I have no experience putting JWH-018 up my nose, but I firmly believe that if it does not work that solubility is not the only reason why.
People say that alprazolam and clonazepam are not effective via insufflation because of extremely low water solubility and I can speak from personal experience to say that is a load of crap. Insufflation is by far my favorite method of ingesting these two benzos (especially clonazepam!!) and for the reasons you would snort anything. Those reasons being faster onset compared with eating it and requiring a smaller dosage to achieve equivalent effects compared with oral ingestion (or more intense effects from ingesting the same amount nasally compared with orally).
For those who were wondering why try insufflating those are some of the reasons. Some people are always looking for "more bang for your buck." Also, at times it is a lot faster and easier (requires less equipment!) to snuff a small quantity of powder versus vaporizing it, and usually snorting would have an onset time and duration that is more similar to vaporizing or smoking than eating a given drug.
So there it is, lol, my rant on the pros of putting drugs up your nose (you did ask why would anyone want to try snorting jwh-18!!)
Cheers