Can I use a camping kettle directly over a campfire?

Stainless steel kettles like the Fire-Maple Antarcti and CAMPINGMOON SW-6 are explicitly designed for open-flame and coal use. Most titanium and hard-anodized aluminum kettles are intended for canister and liquid-fuel stoves; reviewers note that prolonged direct-flame use can discolor titanium and damage the anodizing on aluminum models.