For the route, this is well worth doing. I’ll admit that it’s not a stunner all the way, especially nearer Loriol, but it has nice bits.
After the pleasant climb, with its spectacular view back over the Cléon d’Andran basin to Les Trois Becs and more, you come to the Col de la Grande Limite (sorry I can’t answer the very obvious question), a popular place for picnickers and walkers.
The descent, albeit on a decent road, treats you to a selection of electricity infrastructure to view: wind turbines, and to the south the cooling towers at the vast Cruas-Meysse power plant. I dare say that with binoculars you could see the atomic plant at Tricastin, and the hydroelectric plants at Le Pouzet and les Tourettes aren’t far away. Oh, and there are plenty of pylons and wires because of all that generation. Well, the French have never been ones to hide these things away.
After the descent you also get to see Mirmande (worth a detour/visit). However, the entry to Loriol is disappointing: if you try to approach by the back road (turning right off the D57 just before you meet the main road, and pleasant while it lasts), you’ll be sent down through a housing estate back to the main road, because of a pointless (for cyclists) one-way road.
So, probably not one to make a point of visiting, but a pleasant enough way to get from M to L.