  Scanning tunneling spectroscopy studies on Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$
suggest the presence of electronic inhomogeneity with a large spatial variation
in gap size. Andersen {\it et al} have modelled this variation by assuming a
spatially-varying pairing interaction. We show that their calculated specific
heat is incompatible with the experimental data which exhibit narrow
transitions. This calls into question the now-common assumption of gap and
pairing inhomogeneity.
