One used argument is the depth that the heat treatment reaches to harden the steel till there, deeper than competition / whoever.
There is alot bullshit talk in the specifications towards end-consumers.
Between businesses, actual process names are specified. Alike "electrolytic galvanized". To consumers they (KMC) make that "Rust Buster Technology".
Another one is related to impress ppl with stainless steel. The cheapest (and most common) stainless steel is grade 304. "Made from Grade 304 Stainless Steel", suggesting that grade number is more expensive / less common.
Ex KMC again, they had (ceased) a stainless steel chain. It is stainless, and one link plate is twice as thick as the other.
Stronger? Not really - it's to compensate for weakness of stainless.
And the advertisement only names stainless alike the entire chain is. Not, the pins are not stainless, so rust. And since a serial setup as a chain and also a link in it, is as strong / resistent as its weakest (strenght, corrosion proneness,..) part, the entire net stainless benefit is reduced to at best cosmetics in sunny dry summerdays.