Studying different kinds of organisms in general is important to the scientific community because it can help us discover a lot of information about various topics, ranging from medicine to ecosystems, to biologically inspired materials! As for pandas in particular, scientists mostly seem to study their reproduction and behavior. This could contribute to the understanding of mammalian reproduction and behavior in general, which could facilitate our efforts to conserve nature.

If instead you were referring to the acronym PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections), I'm not sure this is "helpful" to scientists but rather is something that many people are performing research on to develop new medicines and technologies to address these diseases. I hope this helps.

The only pandas I know about are a species of bear living in China. They are bears, but are entirely herbivorous (eating bamboo). They're illustrative of convergent evolution, but I don't know what else you're referring to...