Yes. However if a trader is doing arbitrage trading between two exchanges, why use LN?
Lets say i want to sent BTC from exch A to exch B, btc takes so long. I just look at another coin like Stellar and if safe and profitable, buy STR, send to exch B, convert to BTC, make the usual profit. Stellar already does the job securely and very fast, less than 30 seconds; so why would anyone use LN?
Bingo. For the past year, altcoins have been used precisely for all of LN's stated use cases - that's why the altcoin market cap has exploded. Many more people trust and use altcoins. Due to the network effect, many of those who accepted bitcoin for payment last year now accept altcoins this year. Investors see growth potential in alts now that bitcoin has stagnated. All of this is due to the scaling roadblock. Vitalik wakes up each day and thanks the Core devs for supressing growth of bitcoin.
Altcoins are absolutely superior to LN in every way: No theoretical new second-layer model is needed. LN is basically pointless. But Blockstream has a $75 million bet on LN.
The only problem with using altcoins is that often there is a dependency on notoriously-untrustworthy exchanges...