There are a few I can think of why he might not. The big one is costs associated with getting both, having them put on the board and assembled, and having one version not sell, with those units sitting around. At the very least, they will be wasting space until they finally ship, and it might lead to lack of funds in getting the other version units made. I am not sure how much costs would change to have a run of each done instead of 2 runs with just the -E. In some sense the same may be true of wifi only units, so it may not be an issue at all.
They wouldn't by any chance be very easy to add, would they (such as no soldering)? If this is the case, the US ones could have it added to the wifi only units when shipped to Link and any other US resellers, or we could add them ourselves.