I don’t understand the logistics of: If it is not the reason people come it can’t be essential.

It can be still essential and but people can grasp it after they come here. It doesn’t need to be if A is true B is not true kind of simple. Bitcoin has many features decentralized, censorship resistant, limited supply, self custody..etc. If (let’s say) most of the people come for “limited supply” it doesn’t mean “self custody” is not essential.