I might be wrong but haven't we been bombing ISIS in Iraq, for what seems to be a lifetime, and they are still there. Everyone has seen videos and heard stories of our jets returning with their loads and also the stories of expensively transporting very expensive guided weapons and dropping them on insignificant targets
In fact the 'allied' forces which had been bombing ISIS in Syria for a year inexplicably missed the mile long lines of ISIS oil tankers sitting in the desert which were providing ISIS with the funds to continue their operations. It took the Russian's can-do attitude to actually start taking them out, I'm convinced if it weren't for them the tankers would still be carrying on undeterred.
If the conflict was not so contrived and if there was no doubt that bombing would not creep into a regime changing job I would be more enthusiastic. I still remember what happened in Libya, and the crock of s##t that ended up creating. We did such a bad job no-one dares mention it anymore!
As you can tell, I'm not that hopeful that if we join in it will all end well in a short time.