Having SR-IOV on desktop but not mobile is still better than not having it at all. Especially if customers respond well. Intel is in a rough position as a company right now. Maybe they will decide to implement more chips with SR-IOV if that’s one of the few features they can win on in the short run.
As an aside, Level1Linux has a video about using SR-IOV on desktop already with the new Intel Pro GPUs https://www.youtube.com/watch?v=xii8bqmE6jk