If it's proper hard bastard concrete render, the kind that scoffs at your puny human efforts to make a hole in it, then the little white multi-pin jobs are spot on - they'll go in firmly, and not move. Trying a normal picture hook will, IME, result in the supposedly hardened pin bending, or fracturing suddenly, or (very occasionally, probably if you've hit a pre-existing flaw) causing the render to dinner-plate and flake away.
In mere plaster, of course, no matter how hard it may seem to be, the wee white ones will fail and pull out. Might take ten minutes, might take ten weeks, but they will fail, normally embarrassingly.