There are 137 operating Lightning network nodes (stats: https://lnmainnet.gaben.win).
Soon there will be much more active nodes. Bitcoin will become faster and cheaper thus more useful. The scalability of Bitcoin will increase.<p>Does that mean that Bitcoin + LN will kill many altcoins such as Bcash, Litecoin? What will be the altcoins' next arguments to dominate their main competitor - Bitcoin?
The Bitcoin community has been working on regulations, wall street adoption and security. How about alt coins? Well, they only talk about 2 things: "cheaper" and "faster" transactions. Technology is cool, but if you want to make it you need to seriously work on the real problems.<p>So, to answer your question - YES. As soon as the lightning network becomes part of bitcoin, I think there won't be a need for alt coins anymore. Unless it's something totally unrelated to digital money.
I think some coins main difference is the ease to work with in creating applications and contracts. Plus in some cases coins like Neo that are build around China's regulations are likely to stay and improve in new ways.<p>Also less energy consumption and ease of use are big points. Many alt coins will eventually fail I think, but at this moment they seem mostly linked to how well Bitcoin is doing, so if Bitcoin goes up or down, so will many alt coins at first.
LN is not a Bitcoin-specific technology; it would allow any cryptocurrency to integrate with it. In fact, atomic swaps have been performed between Bitcoin and Litecoin.<p>A more likely scenario is that Bitcoin remains a store of value and people exchange Bitcoin for some other cryptocurrency like Litecoin which they'll use for their everyday purchases.
Low transaction fees and fast transaction time was never a sustainable competitive advantage.<p>Yes, coins like these will need to innovate somehow or their utility will drastically decrease.