What does Litecoin offer over Bitcoin? Litecoin is different from Bitcoin in the following ways, however none of them are particularly useful and on the contrary are only less worthy.


84 million vs 21 millions: since Bitcoin is divisible upto atleast nine decimals and also micro BTC can be used for dealing with low amounts
Faster blocks, 2.5 minutes vs 10 minutes average: six confirmations of Bitcoin are not equivalent of six confirmations of Litecoin, so Litecoin payments are usually confirmed after many more confirmations. It also wastes mining power because in Litecoin, most of the time miners may start work with non-best blocks.
scrypt vs SHA-256: since scrypt can be relatively efficiently run on CPU/GPU, it means botnets can easily control a lot of hashing power. Also, scrypt is relatively less analyzed and used than SHA-256, so it may not be more secure than SHA-256.


Technically, Bitcoin does what Litecoin does in an equal or better way. Also, Bitcoin testnet can be used to experiment with new features.

Why do we need Litecoin that actually has monetary value (around USD2.7 per LTC now)? Is it just promoted by a group of people who missed the Bitcoin get-rich boat?

Bitcoin is a novel concept and early adopters rightly earn their rewards for the risk they have taken.
Well, Litecoin's main aim is to make mining easier for the common man.

The problem with pure SHA-256 mining is that it is not very hard to design hardware that can perform mining at an astonishing speed. We can see this with the currently very much ongoing rise of the ASIC mining industry.

Since scrypt is more complex when it comes to hardware - scrypt not only requires many processor cycles, but also requires intensive memory use - it is harder to design hardware specifically for scrypt mining.

The result of this is that Litecoin mining will be profitable for the average joe for a longer period of time than Bitcoin mining did, when it would be adopted just as fast. Since it does not, the arrival of dedicated scrypt mining hardware will be even more deferred, to the benefit of the miners.

Besides this, I have to agree with you that the other differences between Litecoin and Bitcoin are only minor. Total currency is really not that important since both are very divisible. And faster confirmations are not required either, most Bitcoin transactions are considered valid upon first notice, since it is hard to perform a double-spend attack. (Note that you should better require a transaction to have a fee included when you want to consider it confirmed upon first notice.)
Also, after one confirmation, pretty much all transactions can be considered final.