My answer depends.

Noncustodial: Make it less shitty

Either way, removing the tax requirements would probably help. More merchants accepting it. I would use Lightning a lot more in spite of the aforementioned if I actually could. Mullvad is the main subscription I can use it for. A couple others are Bitcoin on chain. Besides that, everyone wants fiat. I always get a chuckle when Bitcoiner companies or Bitcoin friendly companies only accept fiat.

Nostr is by far the most I use Lightning and I'm mostly doing that as a 'like' button. And I like spending the coin.