The thing is, its the same people interested in both. You will find very few people who shun BTC and love LTC. It will be the same crowd, just working out which offers the best mining opportunities at any given time.
And that's when LTC's speculative value comes into play: volatility and cheap price.
As a BTC hoarder, I don't like my odds in playing HYIPs, bets, gambling, loan, etc, I don't like keeping all my btc on a USB sitting in my safe either. I consider LTC as my own BCST
Because it's so cheap (1:100 after adjustment to
totalmax. coins in existence), I can get reasonable exposure without worrying about loosing them all. If it becomes zero, I'll just tell myself LTC pirate got killed in a car accident and took my money with him