It can be both. The fact that we say "it's cheaper" doesn't preclude "it's more ethical" especially when everybody agrees already that the presented alternative isn't ethical.
Burning coal to generate electricity is both cheaper and more ethical than burning live toddlers. You don't say "we use coal for electricity instead of toddlers because it's more ethical" because that's self-evident to anybody but a true psychopath.
Burning coal to generate electricity is both cheaper and more ethical than burning live toddlers. You don't say "we use coal for electricity instead of toddlers because it's more ethical" because that's self-evident to anybody but a true psychopath.