I do not understand what your writing. The thing that is special about a background layer is that it does not support transparency. All of it will have opaque pixels. If you erase things on a background layer the erased area will have the document background color it will not be transparent.
Many logo file are PSD file or PNG file for they support transparency a background layer in a PSD visibility can be turned off or the layer deleted it not a requirement that an image has a background layer, Jpeg file format does not support transparency its layer will be a background layer.
Better Logo file contain all vector layers. or are Vector file like .svg files. For they can be scaled perfectly.