He may be talking about the RT models, which lack the digitizer of the Pro but still have the ability to run RT versions of apps like Sketchbook Pro

Sketchbook Pro is a desktop-only app; you are probably thinking of the metro version of Sketchbook Express.

Microsoft's own Fresh Paint app is another one that could benefit from this. One thing to note is that all of the Bluetooth styli released so far on iOS are exclusive to Apple's platform. An exception is Hex JaJa, which is cross-platform between iOS and Android, but it's not a Bluetooth stylus either - it utilises high-pitch sounds delivered via microphone.

They also lack Photoshop, though, correct?

Apparently there's an 'Express' RT version of Photoshop, might be what they're referring to?

Yes, I was simply saying it'd be nice to use this stylus on Windows with Photoshop because of its physical/aesthetic characteristics. It doesn't add much technically over the Wacom stylus, might even be slightly inferior, but it will feel different in the hand.

definitely inferior. No pressure sensitivity, which is odd because it does at least sense on/off pressure (to do palm rejection).