I think the implication is that any languages built into Visual Studio get an automatic stamp of approval from corporate management, which is why we get millions of lines of code written in C# and VB.net and not, say, Boo or IronPython. Thus, F# will have something previous ML dialects do not: mainstream credibility.
Of course, one could make the same argument for J# -- which shipped in Visual Studio but is now being discontinued for lack of popularity.
If IBM or Oracle announced their official commitment to Scala, that would be a comparable scenario. It's not just F#, which has been available for a while now. It's that it's now a first-class citizen in all respects.
The technology I can use for real work is to a certain extent dictated by what is acceptable to the organization. Backing from a major vendor goes a long way towards assuring that.
