  We propose to unify two a priori distinct aspects of black hole physics :
their thermodynamics, and their effective dynamics when they are "skeletonized"
as point particles (a useful procedure when tackling, for example, their motion
in a coalescing binary system). For that purpose, the Einstein- Maxwell-dilaton
(EMD) theory, which contains simple examples of asympotically flat, hairy black
hole solutions, will serve as a laboratory. We will find that, when reducing a
black hole to a point particle endowed with its specific,
scalar-field-sensitive, effective mass, one in fact describes a black hole
satisfying the first law of thermodynamics, such that its global charges, and
hence its entropy, remain constant. This shows that the integration constant
entering the scalar-field dependent mass is its entropy.
