For the product there is the option to select with or without sidebar, but selecting the sidebar option and adding a widget means the sidebar is left blank if the widget has no content.
On the other pages we have the option to turn on and off sidebars in the page setting.
We have a few products that will use the sidebar and many others that won’t.
Used a solution with javascript to remove class col-sm-9 from product-image-summary if the sidebar was missing a class from an empty widget.
Maybe no the best solution, but works.
Do you mean that you want to have options for custom widget areas and sidebars position for each individual product as pages and posts have? If yes, so we will take this into account as a feature request and probably add such function in the future.