Nice,
The fiberglass cloth will definitely make a stronger, more durable pot. If you go over 8 inches in any direction, you should probably add wire mesh or other rigid support to keep the pot from flexing.
Did you use "regular concrete"? If yes, the lifespan will probably be short, especially if exposed to freeze-thaw cycles.
There are products for making vertical patches and thin patches for concrete. A thin patch is any use less than 4 inches in any direction. These products are hybrid cementitious and polymer matrix. Some use an acrylic, some a vinyl polymer, and some use other polymers. These are more expensive, but will be much longer lived in use. Cloth or fiberglass cloth soaked in these products will be much more durable.
There is a product called "Shape Crete" - I have never used it, but the videos suggest it is quite flexible after setting up and will resist cracking even in thin applications. Might be worth checking out.