Here is my take on bearings. If you have a new or newer reel and have not had the bearings properly flushed and lubed, you should do so. A good cleaning in an ultrasonic cleaner and a lower viscosity oil make a huge difference, for many people this will be enough. When your reels have a little use on them and they start to become a little less smooth and casting distance seems a little off, I recommend to replace the stock bearings with the ABEC 5 hybrids. In many cases the ABEC 5 bearings are comparably priced with stock replacements. Then their are the guys that want everything they get out of their reels, enthusiasts, tuners, guys that like to throw very light baits on casting gear. I can see in these types of situations where an ABEC 7 bearing run dry will help to lower the startup inertia required to get the spool moving. Many guys that fall into this category opt for micro bearings over the ABEC 7 OS.
Worth is something only you can determine, I stopped using ABEC 7 bearings in my everyday reels when I learned I was not good enough at casting to make proper use of them.
Good Luck