From what I can tell the LN has a ton of technical issues on the backend.
I won't pretend to understand them but @brianoflondon absolutely does.

The biggest problem is that it's only good for tiny amounts and it expects everyone to run their own node or choose a custodian. Even in the best case scenario this makes Bitcoin a better medium of exchange but doesn't help the unit-of-account issue at all: which is the primary tenant of any currency: being able to measure value natively with the currency itself.