Hey, they say there might be negative fees for some transactions https://bitcoin.stackexchange.com/questions/42639/what-are-the-trade-offs-between-transacting-on-lightning-network-and-bitcoin-mai/42653#42653

I think people will keep using bitcoin as they already do. But businesses will probably be paying large lightning node operators for an always open lightning channel to receive payments without commission. And services like Stripe and Paypal will develop in crypto world. This will lead to a more widespread adoption of bitcoin and litecoin, which will lead to price increase. Just don't forget to cash out before it bursts if you think that centralized regulated payment providers for cryptocurrencies will be the end of it.