I'm going to take a wild guess judging by the description of the "Electronics" category that the reason it isn't represented as its own category in the listings is that the products which make up "electronics" usually fall under a bigger overall category definition. For example, almost every "electronics" product can be considered a "household" or "interior" item. Certain electronics items, like a digital clock, would almost certainly be thought of as a household item and again an interior item. So it makes more sense to break down the generalized term of electronics into other categories where they're more likely going to be searched. I think that's why you don't see an Electronics category in the listings, even though it is still available on the site and in search results.