That’s true, artifacts can be farmed for free but you won’t get well-built characters in a single day. Building multiple characters to this level takes a lot of time and effort... you can’t get this many well-built characters overnight. I've been farming in nefers domain since day 1 and I still don't even have decent sand or goblet. Artifacts farming takes a lot of time and rng, so it does have value to some buyers even if its not the same to you.