  The Kondo effect in superconductors is frequently investigated using the
local quasiparticle density of states as sole bath characteristics, i.e., the
presence of anomalous propagators is ignored. Here we point out that this
treatment is exact for a number of situations, including point-like impurities
in d-wave superconductors. We comment on recent investigations [M. Matsumoto
and M. Koga, J. Phys. Soc. Jpn. 70, 2860 (2001), cond-mat/0011256, and Phys.
Rev. B 65, 024508 (2002), cond-mat/0103053] which reached different
conclusions: while their numerical results are likely correct, their
interpretation in terms of two-channel Kondo physics and an "orbital effect of
Cooper pairs" is incorrect.
