For large quantities like 1 whole bitcoin sure.  As the price of Bitcoin rises to the moon, the threshold for the size of the quantity you'd want to do that with will increase.  This would price the average user out, who has never touched 1 full BTC, and make it predominately market makers who'd charge a premium above pure conversion cost.

Therefore, we argue that investing in Lightning now, at the same price as on-chain to arbitrage it is low risk with a decent chance at payoff.