Basically, it lets you select a range on a worksheet, and then shows a live updating picture of that range in a new region (possibly in a different sheet). Why is that useful? Well, the range can contain charts in addition to just cells with data. It can be handy to have the charts actually defined in the sheet where the data is stored, so that let you do this while still displaying the chart in the sheet where you want to show it.
https://trumpexcel.com/excel-camera-tool/
Basically, it lets you select a range on a worksheet, and then shows a live updating picture of that range in a new region (possibly in a different sheet). Why is that useful? Well, the range can contain charts in addition to just cells with data. It can be handy to have the charts actually defined in the sheet where the data is stored, so that let you do this while still displaying the chart in the sheet where you want to show it.