It's nice to have this option, but I don't know why it's _that_ necessarry. I mean, if you want to have your bitmap mapped to an object, than you can enable it to be shown in the viewport. Otherwise I think you can configure your materials and their details in the material editor quite well (in my opinion, Corona has the far best material preview, especially if you increase the quality of it in the corona settings). For the overall feeling usually a diffuse map or color is enough in my opinion.