I was looking at different plans for making a workbench that, one day, I will have the space and materials to make. [One sets of plans][1] I ran into had a board cut and recessed with a handle. 

I have seen lots of bench plans but can't find more than this one using an insert (perhaps insert is a colloquialism?). Sure it makes a wicked paddle but what would the use of this space be?

![Central Insert][2]

<sup>Image from http://www.shavingsandawl.com/</sup>

[1]: http://www.shavingsandawl.com/2014/04/18/workbench-build-part-9-adding-the-central-insert/
[2]: https://i.sstatic.net/Cjy6M.jpg