It appears that Mail does apply Rules to Drafts automatically. With Rules turned on, all my drafts have blue text. Without them, it reverts to the default black text. Until attempting to trouble-shoot this issue now, I had never applied Rules manually.
After turning the rules off, any new message that I compose and save to Drafts does not have any color associated with it. Just black text on a white background. Drafts that were already in my Drafts folder prior to turning off Rules, still exhibit the same behavior. They get the dark blue background when I edit and re-save them. The only difference now is nothing happens when I select "Message > Apply Rules" (since Rules are turned off, there are no "rules" to apply - though the draft messages that had been previously colored by my rule remained colored).
I actually use Drafts all the time. Perhaps I only have time to write part of an email and want to wait until it's complete or until I've thought further about it before sending - it's saved me from sending many an email in anger/frustration until I revisited it with a cooler head. 🙂 Or I'm waiting on information regarding part of my response from another person or I have further research yet to do, or I'm writing a long response and want to save it midway through in case of data loss, or something jumps to the fore, interrupting a message that I'm writing, and I'll need to return to it later. Or, like this response, I'm composing it in Mail for later pasting to the forum because I don't have time to remember why I create the extra Junk rule, but will by tomorrow when I finish this post. Or sometimes, just to clear up my Inbox of things that don't require immediate attention, but that might get lost in the clutter of the Inbox, I'll hit "Reply" and save to Drafts and then it's waiting for me as a reminder when I have the time. Or maybe something - like a birthday wish - doesn't go out until tomorrow, but I feel like composing it now; I can do so and then save it to Drafts to send later. I also used to use it like Notes is used now, but then I think Apple found a lot of people doing that and added Notes. Those are just off the top of my head. I find Drafts to be indispensable. I guess they just fit my work style.
As for the extra Junk rule, I'm still not remembering exactly why I set it up. It was when I first switched from Eudora to Mail, so it was awhile ago. I think it may have been because Mail was not moving Junk to my Junk mailbox properly (even though I've always selected the radio button for "Move it to the Junk mailbox"). Either that, or the default color that Mail uses for Junk was too light a shade of brown and I wasn't getting the custom/advanced options to work the way I wanted them to, so I just made my own rule. I can't remember the reasoning at this point. I'll turn off that rule and see if Mail handles Junk properly for me without it.
Thank you,
Erik