A dahlia and a chrysanthemum trained to carry many blooms are different plants. Compare botanical identity and growth habit rather than relying on a similar-sounding translated name.
Different plants and different displays
Dahlias are grown as named plants with characteristic flower forms and mature dimensions. Exhibition chrysanthemums can be trained into elaborate displays carrying many flowers on a framework.
The Chinese term dali ju can be confused in translation with a similarly sounding dahlia name. In a description of a single trained chrysanthemum carrying hundreds of coordinated blooms, the subject is a cultivation form, not a new dahlia species.
Use names that lead to the right care
Ask for the botanical identity and cultivar before buying. For an exhibition plant, also ask what training and support have produced its current outline.
Compare foliage, stem habit and flowers together. The size of a display does not tell you whether the plant is a dahlia or a chrysanthemum, and the two should not share an automatic planting or pruning routine.
Related reading: Dahlia Flower Forms: Comparing Shapes and Garden Uses.
Horticultural reference
Shenzhen technical guidance: Trained exhibition chrysanthemums