What is the significance of using the command WBLOCK?

Use the WBLOCK command to export these objects as a drawing, which you can then insert into other drawings as a block.

Use one of the following methods to create a WBLOCK:

Method1. Create a WBLOCK from an existing block in a drawing

1. On the command line, enter wblock.
2. In the Write Block dialog box, under Source, click Block.
3. Select the block you want from the drop-down list.
4. Under Destination, in the File Name box, enter the file name for the WBLOCK.
5. In the Location box, enter the location where you want to save the WBLOCK (new drawing file).
6. Click OK to create the new drawing.

 Method2. Create a WBLOCK from an entire drawing

1. On the command line, enter wblock.
2. In the Write Block dialog box, under Source, click Entire Drawing.
3. Under Destination, in the File Name box, enter the file name for the WBLOCK.
4. In the Location box, enter the location where you want to save the WBLOCK (new drawing file).
5. Click OK to create the new drawing file.

Method3. Create a WBLOCK from objects in a drawing

1. On the command line, enter wblock.
2. In the Write Block dialog box, under Source, click Objects.
3. Under Base Point, select or enter the base point for the new block.
4. Under Objects, select the Select Objects button.
5. Select all of the objects to include in the WBLOCK (new drawing file).
6. Press ENTER to return to the dialog box.
7. Under Objects, select the appropriate option: Retain (retains the original objects), Convert to Block (converts the original objects to a block), or Delete (deletes the original objects).
8. Under Destination, in the File Name box, enter the file name for the WBLOCK.
9. In the Location box, enter the location where you want to save the WBLOCK (new drawing file).
10. Click OK to create the new drawing file

I agree with Mr. Yagoup answer .... Thanks

If you want to export a group of objects to a separate drawing file you can use the WBLOCK command to export these objects as a drawing, which you can then insert into other drawings as a block. Creating a drawing that only contains a group of objects is helpful if you are creating a detail library of commonly used assemblies..

Most of us are familiar with the WBlock command for writing objects or blocks to a drawing file. But you must know that WBlock can also be used to dramatically reduce the size of your drawings

i agree with mr. Syed shan haider

This command use to export objects, entire drawing and block to seperate drawings. Which can also be insert into other drawings as block. It seems an "xref" file and reduce the size of drawigns while producing. But this command is not most commanly use for fast drafting and publishing drawings as you have other easy options. 

WBlock is one of the best command to remove error in Drawing.