True, if you have a product that isn't really photographic material, I can understand why you would shy away from Tumblr. However, Tumblr isn't just about photos. You can upload videos, text/stories/blog entries and music. I think it could only help a business if they got crafty enough to use Tumblr. If your product doesn't photograph well, perhaps upload videos showing its use, or have a spokesperson vlog about it.