I'm curious (truly curious, not meant to question or attack in any way): what do you guys foresee using this (or any linux based tablet without a keyboard) for?

I'm trying to imagine how I'd want to use one myself, and I can't come up with much as it's not an all-in-one package I can carry around nor is it built for productivity. If I needed productivity, I think I'd rather stick with a more traditional, better supported laptop solution where I'd also get more bang for my buck (at least currently).

I think of tablets as a device for information consumption, and in those terms, I don't really have a preference for a particular OS as long as the apps I need and widgets I'd like are supported. However, with a capacitive touch device, I'd prefer apps designed for touch interfaces quickly working their way towards more stability and functionality rather than very stable, full featured apps that aren't getting very much love (if any) towards reworking the usability aspects. I can imagine feeling the opposite way for a device that that had a keyboard, mouse, and/or a more accurate touch screen solution, but that's not the case with this tablet.

Does the Spark variant it still have the Android capacitive buttons from the C71? Looks like. If so, why?

Why? Because it's much cheaper to reuse existing hardware than design new hardware.

beacause they are just buying 120$(with shipping) android tablet, flashing gnu linux on it and selling it for more than twice its original price(without the price of shipping)

Usually a low price means that a large quantity was bought. I suspect the first run of this will be a low number, both for lack of bootstrap funds and to avoid sitting on a large stock of something that is unlikely to get as much attention as Android.

I may get one for my wife. She just wants to use the web and a few other basic things. This should fit the bill just fine and give me a toy to ply with.

That's why i asked, exactly. (for me) There's no point in a 100% premium (way less would be quite ok!) when the hardware is unchanged; i could just buy the Droid then. Or is there a difference in bootloader etc.?

i dont think so, im almost certain that they are simply buying the android tablet and flashing the new OS image, probably with the same flasher used for flashing android on that same tablet, and than charging alot of money for GNU/Linux that is supposed to be free(and here it costs as much as windows...)

This is the freerider's dilemma. What if everyone makes the rational choice to buy the cheaper tablet? That may jeopardise the project.

that applies only when that device is not already on market with a much lower price tag, if this was a new device specially made by some manufacturer for them with their design in low quantities than your claim would be valid, in this case it is not