Response is a spectrum of time it takes from when you give the yoyo slack to when it actually returns. Semi-responsive in this context means the yoyo has a narrow gap width and a lubed bearing (it is a responsive yoyo), but with some play as the lube breaks down/escapes the bearing it’ll gradually start to take longer to respond. Think of a Freehand that you’ve played for a long while, where you’ve worn down the response and the bearing is starting to spin more freely.
The greasebucket bearings alleviate this by helping the grease stay in the bearing, so the response stays quick and snappy for far longer, ie it stays fully responsive with less maintenance. If you didn’t pick up a greasebucket bearing, you can still just add more lube periodically to keep the response where you want it.
I’m now part of the Deepest State. I haven’t tried it yet with the Greasebucket. Which is one of the coolest names, which I wired into a couple Fenders. And if I could order a custom color it would be the blacker than black Cerakote. One Drop black.