Flowtoys worked with Henrys Juggling to develop versions of their grip and smooth bodies specifically for our glow clubs, with the ideal amount of light diffusion, and lower weight to perfectly balance the electronics. They are also slightly softer, which has been well received.
Henrys designed the grip body to make the body of the club easier to catch/grip - this also helps with contact club manipulation. One of the common praises is that it does not require the break-in time that smooth clubs require to develop some stickiness. Many jugglers who give it a serious try prefer it.
The grip body has a unique advantage on glow clubs, because it obscures scratches that are otherwise well illuminated on the smooth body and the grooves are protected from scratching at all, though they can also retain dirt/mud in some conditions. The grip body also adds a distinct look that goes well with the LED pixels visible in the handle.
All that said, many people still prefer the classic aesthetic of the smooth body, and the smooth feel during manipulation. They both have their place, and you can easily swap them out by unscrewing the knob. Extra bodies are only $5 each so you can try them both.