To answer your first question - they say X times because often the bonus will be based on your deposit amount, which could be less than $100, so if you deposited $20 then obviously your total wagering requirements would be less than $6000. To answer your second question - new regulations mean that casinos must clearly display the wagering requirements and other terms next to each bonus offer, and the standard is pretty much now to say "bonus must be wagered X times" or "X times wagering applies".
