You are absolutely right. How to contain the hydrogen and oxygen safely in a home? How to supply the expensive and rare platinum catalyst for the hydrogen anodes in thousands of homes? Not to mention the fancy electronics required. Way too expensive. There are other factors - clean-up after homes explode from faulty units, EPA approvals, etc.
However it seems the Japanese how made some progress.
http://marketplace.publicradio.org/display/web/2009/12/08/am-home-fuel-cells/
Don't underestimate advances in catalyst chemistry.