[metaphorm]

the land (and house, usually) are used as collateral in home mortgage lending, which is a major category of lending but not nearly as foundational as Federal Reserve lending, which is the basis of the entire fractional reserve banking system.

there are many other categories of credit that rarely use land as collateral. small business loans don't (or almost never do, in any case). corporate bonds don't either. consumer credit (including student debt) is totally non-collateralized.