Hi Moka. You can use it for whatever suits you best.

I use it as a temporary hold - for example, I'm working on a project, but other priorities crop up so I decide to put that project on hold just for a couple of weeks, but don't want to move it all the way back to my Someday Maybe folders.

And all of the contents of my Someday Maybe folder are set to On Hold too, so that none of the actions appear in my active lists.