Spaces like that are more common than you’d think when it comes to countertops. Some older kitchens used that space for lazy Susan style rotating shelves, but you don’t see it much anymore.

The blocked-off corner space is what happens when you buy pre-made cabinets instead of having them custom-built. (Unless the cabinet manufacturer happens to offer a dedicated corner piece, and the measurements work out such that it fits in your kitchen, I guess.)

"Oversized" and "cheap" are relative terms.

Also, not everyone obsessively buys and hoards crap they don't need. My kitchen cabinets are half empty, because I don't buy things like air fryers, and bread machines, and food dehydrators, or whatever the latest single purpose cheap appliance is.

I use it for things I rarely ever use, like the microwave.

I would get rid of it but sometimes when we invite people over to have food and they bring microwave meals.