plus it can be sent over the wire, "packed", "minified", eval'ed at will, etc... no idea why trying to reinvent the wheel 
PS: I would greatly benefit from it, since JS is my main coding language
PS: I would greatly benefit from it, since JS is my main coding language
I think this mostly comes down to the fact that Java and its miscreants are the Devil.
And still anyone with the skills could implement a javascript client. If ethereum really breaks through there will be a lot of opportunity for new development. I think its a good thing to see there are already multiple prototype clients in multiple languages.