  In ferromagnets, magnons may condense into a single quantum state. Analogous
to superconductors, this quantum state may support transport without
dissipation. Recent works suggest that longitudinal spin transport through a
thin-film ferromagnet is an example of spin superfluidity. Although intriguing,
this tantalizing picture ignores long-range dipole interactions; we demonstrate
that such interactions dramatically affect spin transport. In single-film
ferromagnets, "spin superfluidity" only exists at length scales (a few hundred
nanometers in yttrium iron garnet) somewhat larger than the exchange length.
Over longer distances, dipolar interactions destroy spin superfluidity.
Nevertheless, we predict re-emergence of spin superfluidity in tri-layer
ferromagnet--normal metal--ferromagnet films of $\sim 1\, \mu$m in size. Such
systems also exhibit other types of long-range spin transport in samples
several micrometers in size.
