Having your product shot on black or white or both rarely comes to mind as often as it should. Large online retailers might require solid white backgrounds for your product images but is everywhere else you want to show your products on solid white? Everything except the background is identical in these two images but you can see small variations in highlights especially along the edges. Social media sites are offering dark themes more and more, how bright is your website, do other resellers offer a dark theme on their site? Your graphic designers can certainly clip the product from the background and place it on anything they are using but the minor differences can distract the viewers eyes as unnatural or awkward even if only at a subconscious level. If you intend to clip your product regardless, your photographer can pick a background contrasting your product making that easier but it won’t give quite the same look as separately shot images. What’s easiest for your photographer isn’t necessarily what’s easiest on your viewers’ eyes or what will show the best colors and details. When ordered at the same time creating and delivering both images is much more economical and gives you the exactness above compared to having to order a reshoot later.