It visualizes the distribution of data over a given period, and the peaks show where values are concentrated.

As such density plots work better at determining the distribution shape (the concept of the shape of a probability distribution arises in questions of finding an appropriate distribution to use to model the statistical properties of a population, given a sample from that population) because they’re not affected by the number of bins.

The most well-known form of density plot is kernel density estimation, where a continuous curve is drawn at every individual data point. Then all of these curves are sum up to make a single smooth density estimation.