Like you pointed out, there's a fundamental difference between the transfer of a bitcoin, and the transfer of a token that represents a claim on some external-to-the-blockchain property.  In the later case (asset-backed tokens), all that is transferred is ownership (and ownership is really a social construct, valuable only to the extent that one's society is willing to enforce property rights [as control of the property in question remains a physical problem]).  In the former case (bitcoin), what's transferred is control itself.