Why would I need to alter bits?

[91vUpfjN]

I'm referring of course to the bitwise operators in the beginners section of the tutorials.

I know what they do and I know that there's a useful shortcut using >> or << for some instances but generally what's the point? So far whatever I can do with << I can do with normal arithmetic operators.

Can someone point me in the right direction of more information about the whys?

Edit

Answer:
http://www.cprogramming.com/tutorial/bitwise_operators.html

Speed and Space. Bitwise operators can be used to manipulate both if space/processing power is at a premium.