for those assets, what are the advantages of decentralization? other than the one-offs we hear from Patrick Byrnes enabled by unsound money, when have you had stocks, bonds, or insurance contracts reneged upon?
If you want to turn those kinds of contracts into bearer instruments, representing them as tokens on a blockchain improves the ability to transact in those bearer instruments.
Many people have a problem conceptually separating the need to trust a counterparty to fulfill a contract, and the need to trust a ledger system to accurately record ownership information.
It's possible to make the latter arbitrarily small, but there's no technological solution to the former as it's inherent to the problem space.