With adequate well drained soil mix, any material will work, even plastic. Stop the non-sense that the walls must “breathe”. It´s the substrate aeration that´s important. If you use clay soil in a terra cotta pot your chance of rotting your cactus or succulent is pretty high. BTW , in 2000 , I worked as a plant propagator in San Diego : about 6 millions cactus per year produced all in plastic pots , very , very few died. Plastic is cheaper, lighter, and comes in all colors and shapes – terra cotta has more “charm” , it´s ok but not for mass production.
