Damn, I wish someone would have told me there can be only one store of value before I bought gold and silver. I guess its against the law and was stupid of me! Also see my last response about fiat and market caps and such.
wow, that was a long post, I want to answer only the store-of-value argument, as the rest is not so important.
Gold and silver metals both have
unique properties and neither of them can replace each other, that's why
both are valued by humanity.
BTC and LTC are the same minus a few insignificant technical details and can perform the same functions, that's why only one can be valued, and all things being equal, the first one that came into market is and will be valued, there is no place for two store of value assets here.
Neither BTC nor LTC fits into the every day currency category though, as they are too rare for that.