It's a little small of you since file extensions generally have no actual relation to formats. There's nothing stopping you from naming yours .wbp, although I wouldn't expect most programs to accommodate you.
I just changed one to .wbp to test with paint.net. The Open File dialog doesn't even have a mask that allows me to show the file. Dragging and dropping resulted in the program complaining, "The image type is not recognized, and cannot be opened" despite WebP having a recognizable header. But I lay that at the feet of the application, not the format.
In the end, it's okay to be a little small sometimes. I've held grudges for less myself.
I just changed one to .wbp to test with paint.net. The Open File dialog doesn't even have a mask that allows me to show the file. Dragging and dropping resulted in the program complaining, "The image type is not recognized, and cannot be opened" despite WebP having a recognizable header. But I lay that at the feet of the application, not the format.
In the end, it's okay to be a little small sometimes. I've held grudges for less myself.