It is probably more to do with marketing than anything else.
There is that, of course. And then the niche market item has value beyond direct monetary profit.
With video, when you go to prestige items, you end up with cinema cameras and lenses.
So maybe Panasonic is doing the same as you've just stated about the marketing value of prestige niche items. Panasonic needs an angle in the market, and maybe "affordable" high-quality video is it. The strategy would then be to launch a full-featured camera (the GH4) now and then about six months to a year later a stripped down (aka crippled) version for the masses.
It could also be that Panasonic wants to get into the "real" cinema camera business. But that is expensive and a huge gamble. So, what do they do? Well, apart from the size of the sensor, everything will be the same, because its the same amount of data ... because, as I've said previously, 4K is 4K, irrespective of the size of the sensor. The GH4 could be a proof of concept camera, a testbed for the technology, and bloody good PR if they pull it off. (And if they don't, then they haven't made idiots of themselves in the "real" cinema camera business.)
So, how does this affect Canon? Well, it will mean that Panasonic becomes a direct competitor to not only Canon's Cinema EOS range, but also their "mainstream" aspirations.