You appreciate LTC because it was a copycat of BTC?It has no use since there is no need for number 2.
There is a need for a number 2.
If there were several different coins with the same utility as bitcoin, we wouldn't be having a block size flamefest right now.
Like Linux distributions. If like me you like RPM, you use RHEL or SuSE or Fedora.
If you like debian packages you use Debian or Mint.
If you don't value privacy and don't mind Amazon tracking you by default you use Ubuntu (yeah yeah I hear they fixed that...)
Competition is good for the market, monopoly is not.
Bitcoin for all practical purposes has a monopoly. That's why people are fighting over who controls it. Monopolies have a lot of power.
Finally someone who gets it. I am tired of people saying we dont need altcoins. If bitcoin is the only coin in the future we will actually have a worse financial system than we have now, bitcoin is huge and it is entirely possible that at some point in the future miners could get greedy or bitcoin could be attacked. In a case like this people will need another coin they can transfer to. Bottom line it never hurts to have alternatives to fall back on if something goes wrong down the line.