It's a totally relevant! Rather than test LN and its base code SegWit, (bitcoin's DAO), in the real world befor deploying it on a $10B network
LN's basecode is not Segwit. I'm surprised that you have been fed false information. Segwit is not Bitcoin's DAO and is not even as complicated as some people say that it is. Most of the codebase is just automated testing. LN could be created (AFAIK) without Segwit but it would be much harder. why shouldn't SegWit be deployed and tested in the real world on an altcoin before being implemented in Bitcoin?
Nobody is preventing altcoins from implementing Segwit. I'm 99% of sure that if the Core developers decided to wait for this 'testing period' that the 'shill campaign' would complain everywhere that Core is stalling progress, fee market panic and other rubbish. 