There should be no issues introduced by enabling hybrid spectrum analysis on your APs. You will gain the benefit of devices getting classified and that information getting sent up to AirWave for reporting, locating and long term storage.
Spectrum processing does take a little bit of CPU resources. In normal day to day operation it should have 0 impact on your network. The maximum throughput of the AP may be brought down ~5% in some environments. But if you are maxing out the throughput of your APs, you have bigger problems on your hands than the 5% performance lost to hybrid.
I would recommend enabling it on a few APs for a week. Once you have tested it, you can safely enable it for all of your APs.
Dedicated SMs are good but they won't be hearing the exact same interference as the AP serving clients since they are physically located in different spots. Hybrid gives you visibility into the channels your network is using, where it is using them.