As @sylumer mentioned, you don’t really need to think about where to store your drafts. No folder hierarchy or save as equivalent has to factor into your thinking at any point. This can be disorienting at first when thinking about Drafts as a long term space for your notes.
But it’s actually quite liberating. Because instead of building elaborate storing structures you can just worry about being able to call up the drafts you want when you want them. Tags, absence of tags, flags, and word or character choices are your note tools. Tag filters, searches and Workspaces are your finding and grouping tools.
How you choose to use them is often a personal preference.
I wrote a long post with my thoughts on this stuff if you are interested.