We investigate the maximal outreach of soft, elastic robotic arms with controllable intrinsic curvature by using the three-dimensional geometrically exact Cosserat rod theory and a linear elastica model. We compare results with previous predictions for rods without intrinsic curvature based on a planar rod theory. We point out that planar models often overestimate the maximal outreach achievable by arms not constrained to a plane per se, by neglecting instabilities associated with spatial configurations. At the same time, intrinsic curvature can be utilized to stabilize the rod. Here, we study the interplay between spatial buckling and intrinsic curvature on a clamped, prismatic rod carrying a vertical tip load. The numerical solution of the associated boundary value problem and discrete stability tests on the obtained equilibrium solutions reveal significant improvement in the maximal outreach, especially for arms with wide and flat cross-sections.