Then why is there a WiMAX version?

If this mantra (that WWAN connectivity is supposed to come from a companion device) was so true, then Nokia would have released a WiMAX router, like the CradlePoint Personal Hotspot or something, instead of a WiMAX edition of the NIT. And THAT would have been where the WiMAX connectivity for the NIT came from.

Of course, there's the third option: Nokia wasn't thinking coherently when they entered into the WiMAX deal, and so the "NIT is supposed to pair up with [another device]" mantra isn't true, but they're also not going to follow the WiMAX edition to its logical conclusion (a GSM/UMTS edition). Or perhaps they were told from above to do the WiMAX edition, but the end result is the same: no such mantra governs the product group.