This announcement makes a fair amount of sense. It fits in with the difficulties & delays in creating IMS-capable handsets, and the trend I noted the other day of fixed-VoIP being a lead IMS app, even for mobile operators, and often implemented on PCs.
Laptops are clearly even better than desktop PCs as IMS end-points from an operator standpoint - they have a reasonable chance of being "mobile" or at least nomadic, and they roam from time to time. (I'm writing this in an unseasonably cold & snowy Dallas). And PCs are much easier for developers to write applications on, they've got the horsepower & battery to do VoIP and multimedia, they're inherently multi-tasking and best of all, they're not usually subsidised.
Now, the announcement also talks about embedding HSPA in laptops. I've said before that I'm unconvinced about cellular embedded in PCs, for various reasons, and I still believe that it will not become widespread - maybe 10-20% of laptops shipped in a few years' time seems a reasonable range. On the other hand, a PC has a bit more room for a decent-sized antenna, so perhaps HSPA reception might improve vs a phone - although as with all 3G devices you're at the mercy of patchy indoor coverage.
On the other hand, unlike phones, all HSPA laptops will have both WiFi and a wired ethernet socket as alternative accesses, so the chance of getting some form of low-latency high-bandwidth connection for the IMS client is much higher, especially as once again the nature of the OS and the device makes it easier to write multi-mode connection software clients. They also don't tend to be used while actually walking around, so you can forget about all the overhyped distractions of "seamless handover".