When asset prices rise or fall greatly it can be difficult to measure the interest levels across time periods. Think of assets like BBBY, GME, CVNA, BTCUSD, etc... :)
This simple visualization multiplies a pricing option by the volume to give a "dollar cost" volume over time. With this, you can more easily measure interest levels from "smart money" ("big money") and eliminate some of the noise from large volume moves when prices are very low (or small volume moves when prices are very high).