The most common is to express abstract things with concrete things.
A dream is a flower, and only when the water and soil conditions are met, it is possible to be delicate and open!
In this sentence, dreams are very abstract things, but compared to flowers, it is easy to think of that kind of beauty, and dreams need conditions, just as flowers need water and soil to be delicate and open.
But if it is the other way around, using concrete things as metaphors in the abstract will make the simple complex, increase the cost of interpretation, and be detrimental to the spread of products and brands.
Or using one figurative thing as another figurative thing is not only wordy, but also meaningless to increase the steps of understanding.
It's like saying, “Your skin needs water like a plant.” It's not as straightforward as saying, “Your skin needs water.” And it's easy to see.