Is it worth? What if the game actually never comes out?
Oh, you just want to make me go "what could POSSIBLY go wrong", don't you. =P
I say it is worth spending whatever you want for the game, if you can afford it. It's pretty much set in stone that we will get a game out of this kickstarter campaign, and although the pessimist in me is pretty convinced that it will never be able to match the insanely hyped up expectations I'm confident it will be at least passable.
You need to ask yourself the question: What are 40 bucks to you?
Can you throw them at this project and gamble on the results?
If so, I say go for it. If not, then spend them on something more important.
It really depends what these 40 (or more) bucks are to you, and what the name Chris Roberts means for you.
Me, personally, I melted down my Wii U funds and funneled them into this monstrosity. Not in one go, but gradually, over time. First was the 60$ 300i pack. Then came metal cards, ship skins, more ships, even more ships...
If this fails, then it fails. Nothing I can do about it. Sure, I will curse and whine and cry, but I went into this fully aware of what was going on. Now, if
Braben botches Elite Dangerous, that will be a sad day for me and you'll probably never hear the end of it. Don't even know why.