From a tactical and operational perspective this can become a strategic mis-step given now you have forced ISIS to disperse its forces and move against some of your most vulnerable assets.
If you are going to attack Al-Raqqa than you must have shown the ability that your CF can close the rest of the avenues open to ISIS operations. This action will place pressure on the KRG fronts and flanks in Erbil and Ankawa, and Baghdad over the next few weeks. For the Assyrians in Nineveh Plains and the remaining of the Khabur river valley be ready to deal with some ISIS pressure.
ISIS has shown the ability that it can flex when attacked in a location. It is the reason why it has expanded in the Sinai, Libya, Tunisia, Afghanistan, Nigeria, and even India.