One reason is so that your internal testers won't have wildly different experiences. It's much easier to verify one UI than several slightly different UIs. Th

One reason is so that your internal testers won't have wildly different experiences. It's much easier to verify one UI than several slightly different UIs. This is similar to the cross-platform user experience, but even companies with very few cross-platform users will usually have a testing department, and have to worry about educating them with the product. 2, 3 or more different interfaces will add a lot to the burden of educating new QA folks.