  The Virtual Compton scattering (VCS) process at low energies explores the
electromagnetic structure of the proton in terms of generalized
polarizabilities (GPs). In the one-photon exchange approximation, VCS can be
accessed with exclusive photon production reactions with electron or positron
beams. The extraction of the GPs from VCS with electron beam has seen
substantial progress over the past two decades. Nonetheless, a consistent
picture of the GPs from low to higher scales demands further investigations.
Complementary measurements with positron beams offer an unique possibility, and
we present an impact study of such experimental program.
