With photoshop smart object, you can't simply unpack the contents of it to the current document layers.
Think of it as an external file that is linked to your current document.
To edit the smart object, you can double click on the thumbnail in the layer panel, and it will open up the external file in your photoshop, and all the inner guts of the smart object. You can edit the content now. However, if you edit your smart object, all other documents that references this smart object will also see the changes.
If you want to bring all inner layers to your main document, you can select all the layers and drag it out of your smart object document to your main document.
The benefits of smart object is, it is a shared resource that preserves original data of the contents in it.
Things you can do:
- Perform non-destructive transforms. Scale, rotate, skew, distort, perspective transform, or warp a layer without losing original image data or quality because the transforms don’t affect the original data.
- Work with vector data.
- Perform non-destructive filtering.
- Edit and automatically update all its linked instances.
Things you can't do:
- Actions that will alter pixel data. If you convert the smart object to regular layer without above process, it will be rasterized.