besides everything else, monero just isn't practical or appealing to merchants operating in public. too slow, and too expensive. and not to mention tainted with shadiness.

Judge: "Oh you like Lightning solely because you want to save on transaction fees? You can transact for free on Cash App, Paypal, Zelle, etc"

Come on. Your supposed deniability easily falls apart by even your own logic. You can't avoid this with either Lightning or Monero without adding sovereignty/self-custody/permissionless txns into the combination of reasons. Otherwise it makes no sense.