The thing about many objects for the garden is that they have to be both ornamental in design as well as being incredibly practical. That is, they have to look great, but they also have to work well, to make your garden beautiful and practical.
Let's take those stacking pots as an example. They certainly fit the bill of looking great as they enable you to grow a tower of cascading flowers for the maximum visual effect. But it is their design which is possibly even more important as without their unique watering tube they would be useless and the flowers would die through lack of water.
So many gadgets for the garden are designed to look good but they lack substance and design and end up a hindrance rather than being any benefit. I have bought things in the past which I thought would make my garden look great, only for them to end up in the bin as they lacked the right level of design.
Gardens are hard enough to look after as it is, without having to spend extra and precious time on things that we should not have to worry about.
So next time that you buy something for the garden, check that it is going to work well, as well as looking good, or you may end up throwing it away.