I think that compared to wedding rings, the collar significates ownership in a stronger manner, and while wedding rings are worn by both partners, the collar is from the Master to the submissive, which marks the dynamic of the relationship differently.

There is something both sophisticated and primal I believe, in the fact that a Master collars their submissive, especially when the collar is to be worn for long term or in a permanent way. Yet, I think that it is the symbol itself, more than the visible, more obvious aspect of certain collars (are due to vanilla contexts such as workplaces, a more discreet "collar" life item may have to be picked) that matters. In my view, it truly comes down to ownership.