I supppose the main questions are, should you speculate on the value of BitCoin going up? Or even down? Will BitCoin become the benchmark currency in the future, or is it a flash in the pan and regular currencies will reassert themselves? Those are interesting questions, but they're more to do with trading than betting and thus outside my area of expertise.
In terms of betting the way I've decided to look at it is that BitCoin is already a gamble. The value of a BitCoin goes up and down so much that any investment is fraught with danger. Taking that into account, why would you use it to bet with as well? It's a gamble on a gamble. It's like buying shares in an internet startup and then wagering them on a horse........at long odds.
If you're into matched betting the idea is that you minimise your risk and are taking small (ish, they do add up!) profits consistantly. You might think that takes some of the fun out of gambling, and maybe it does, but losing is never fun. Using BitCoin as a deposit method is like anit-matchedbetting. It's putting an unecessary risk on one side of your equation.
I've written up some more on the subject of BitCoin betting and linked to some other useful information on the subject. But really, just don't do it!