That was indeed a autocorrect issue, and if that was what caused the confusion, I apologize. I've also done nothing but reiterate the same point from the start, which you seemed quite opposed to consider. This has also devolved into name-calling, so, not sure why you bothered at all.

Even if admittedly, the word "usable" (hard to misunderstand in the context, IMO) should have been "useful", the usable part of this could very much have been for other knowledgeable software developers/designers for it to be the backend of something user-friendly. As such, not even "usable" in that context would have been wrong. Regardless, this would require some modicum willingness for benefit of doubt, which, I do not expect at this point. My only advice to you, is that perhaps don't assume people are children, and perhaps you'll find it easier to see meaning in their arguments.