On the whole tablet issue, I personally do believe tablets are useful, as phones don't have a high enough resolution to efficiently move about the device. An example being that watching a movie on your phone is going to be incredibly anti-climactic due to the small size, that and typing in general is going to be more difficult because of the smaller keyboard compared to tablets. Another personally applicable example is where you have games that require specific touches at specific times (osu!, TapMania), a smaller screen can hinder this very important game mechanic. They essentially serve as a more convenient, portable laptop without a keyboard.
Tablets in general are useful, however I believe that other tablets (I'll use the Nexus 7 for this example) are much more worth the price than an iPad, which only really has a larger collection of (questionably useful) applications going for it, most of which are
usually available on both devices in different forms. The Nexus 7 probably has much more capabilities in terms of software features, customization and development options (without rooting/jailbreaking).
It's fine if you prefer the interface of iPads over android tablets or the like, but you're paying twice as much for it, and I'm surprised that the people who buy iPads for full price (or through some other payment method that would equal to the selling price) don't question whether or not it's
truly worth buying. If you didn't pay full price, then it's perfectly fine, as it pretty much comes down to preference in deciding to buy a tablet.
And it's not like it requires INTENSE CONCENTRATION or anything, it's just video editing.
Actually, often times, you'll need to align clips to a certain, specific point in time in the video, and you'll need to enter specific numbers for different effects, transitions and such. This isn't very feasable in a moving environment.
Though I digress; I don't even see why you would use anything else other than a PC/Laptop for video editing.