With the purpose of developing an open discussion on the physical meaning of the alternative BF formalism to account for gravity, we review some known basics on the first order formalism for General Relativity and on its constrained BF formulation. We recall transformation properties of the gravitational field in this formalism, and recall the expressions of torsion and curvature for an internal gauge formulation of gravity. We raise questions on the equivalence principle and its link with the so called "gauge principle", within a principal bundle formulation of General Relativity and other gauge theories. We conclude with a critical discussion on the perspectives for a unified description of forces and raise questions on eventually related physical consequences.