It is thicker, more substantial, better made. Compare a new trellis or garden arch with an old one. Look at an older patio set versus a new one. If you can see the difference, you can see one of the appeals of the old. Some people like the contrast of the materials with the greenery.
Contrasts can add interest.
Imagine a shady bed of hosta by itself, and then add an urn, with impatiens or trailing ivy. It just got better. Some items actually work, and that's their value. Troughs provide water for birds and pets. Hewn stones and antique splashblocks look a lot better taking the water away from the house than the hard rubber ones do.