  It is shown that the magnetization rounding measured by L. Li and coworkers
above the superconducting transition in optimally doped YBa2Cu3O7-d crystals
under magnetic fields up to 14 T [Phys. Rev. B 81, 054510 (2010),
arXiv:0906.1823] may be explained at a phenomenological level in terms of the
mean field Gaussian-Ginzburg-Landau (GGL) approach for layered superconductors.
This result challenges the claims of L. Li and coworkers, who write '[...] we
are observing the phase-disordering mechanism, rather than Gaussian mean-field
fluctuations', but it is in full agreement with earlier magnetization
measurements by different authors in optimally-doped YBa2Cu3O7-d under lower
magnetic fields. The adequacy of the mean-field Ginzburg-Landau descriptions is
further confirmed when analyzing in terms of the GL scaling in the
lowest-Landau-level (GL-LLL) approximation the magnetization data reported
below Tc by L. Li and coworkers.
