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.
That was a pretty bad argument.
Bitcoin was hardly worth anything two years ago.
Who knows how high Litecoin can go?
Hmm, I think that was exactly my point, why I started at Litecoins after a wrong attempt at Bitcoins. I directed my GPU's at bitminter with the easy-to-go Java client an earned something around 0.0001284 BTC. Believe me, that made me not very happy.....the amount is still parked at bitminter, as its not worth to use the payout.
So I changed to LiteCoins and earned a few coins within a few days....TaTa !!!!!
Beware, I'm a late starter in this and may not be aware what was 2 years ago. I just care what is NOW.
Ok, after 3 or 4 Months I'm back at BitCoins, but with much different hardware. And let a few leftover GPU still mine LTC.