Acid chlorides and reduction by hydrogenation
Hydrogen gas and platinum metal simply work here because the C=O part
  of the acid chloride is flat.


It's more than just that.  Acid chlorides are significantly more reactive towards catalytic hydrogenation than other carbonyl compounds.  They are reactive enough that a poisoned catalyst must be used along with mild reaction conditions to achieve reduction to the corresponding aldehyde, and have the reaction stop there (Rosenmund reaction).

So the question becomes, "why are acid chlorides so reactive towards catalytic hydrogenation."  It is thought that because the acid chloride $\ce{C-Cl}$ bond is so reactive that the palladium inserts into this bond to form intermediates such the one pictured below.  



Other typical carbonyl compounds can't form such an intermediate; consequently acid chlorides are noticeably more reactive towards catalytic hydrogenation. Anhydrides, where the carbonyl is roughly as reactive as an acid chloride's carbonyl towards nucleophilic attack, have not been reported (to my knowledge) to produce aldehydes under Rosenmund conditions supporting this mechanism involving a palladium intermediate.

Historical Note: Prior to the application of metal hydrides to the reduction of carbonyl groups, the Rosenmund reduction was a major synthetic tool for chemists.  It was one of the few methods available for the straightforward transformation of acids, esters, amides, etc, to aldehydes.