Ill give you the answer right here...

 Because Bitcoins are expensive for most people, lets face it, when someone invests or buys something like this, they do not want to have a balance of 0.250304  etc... they want to have whole numbers... why? its just the way it is, we dont want to have a dollar bill that actually reqads .0354 dollars.. we want whole numbers.. I know it sounds stupid, but studies and common sense say thats what we like to see and hold.

 Therefore, Litecoins provide most people who cant afford, lets say 50 or 100 Bitcoins, but they can afford 50 or 100 Litecoins, the silver to Bitcoins gold... People can have a prettier whole number to hold onto with Litecoins.