If it is bitcoin, why not call it BTC.
Because Lightning Network is trustless. However, if you have a federation, and initial signers are still needed, then that federation is far from being trustless. You cannot even change them, so it is the same problem, as with "signet challenge": once deployed, you are doomed to live with it (of course, it is possible to add some better mechanism, and then compromise initial keys, but nobody is planning those kinds of actions in the near future).
But not only that, it is not also included in any of bitcoin BIP.
When it comes to LN, some people think, that LN-related improvements should be also BIPs. But well, LN by itself, is far from being added into Bitcoin Core, so as long as it is the case, there is no strong incentive to make BIPs like that.
There are many other coins that are altcoins but pegged with bitcoin.
In which ratio they are pegged? 1:1? Some other constant? Because if it is just UTXO-based, and it contains only some dust, no matter how many ALTs are created, then it is far from being "pegged", because there is no "peg", if you can produce new coins, out of thin air, and if there is no fixed BTC:ALT exchange rate (in LN, it is 1:1000).