What does Nano bring to the table, why not use the lightning network?
Nano is faster, simpler, and cheaper (0 fees) than the Bitcoin Lightning Network. LN unfortunately has some design-level issues that can't easily be abstracted away. Nano on the other hand is pretty simple, which is its strength (makes it easier to develop and secure).
LN isn't a solution for one off peer-to-peer payments. You first have to open a channel on the first layer (which costs fees and time), so LN primarily helps in cases of repeat transactions, not one off peer-to-peer transactions. You also have to pre-commit some amount of BTC AND all channels routing to your destination must have enough BTC to route your payment.
- Requires opening & closing channels on the first layer (costs fees + time)
- The first layer currently doesn't have enough TPS to onboard even a PayPal level of users that want to use LN
- Must be online at all times
- For core nodes, private keys must be held online
- You must pre-commit BTC capacity to fund channels
- Some of your channel capacity has to be reserved to close the channel
- The cost to close a channel can fluctuate, potentially trapping your BTC
- If a channel is force closed, you have to wait for your money to be returned
- The seed is not enough to recover LN funds, you have to backup current state
- LN routing is not a solved problem
- Optimal LN usage will be through centralized hubs that route payments for you (who will probably require KYC)
- LN requires some level of trust (hence Watchtowers)
See page 49 of the Lightning Network whitepaper: https://lightning.network/lightning-network-paper.pdf
Here are some video comparisons of the two: