The WordPress switcheroo worked. I had to change me email address in WordPress and, I wasn't sure if the domain would be treated like a regular domain or like 10minutemail.com (which a lot of places summarily reject.) As I mentioned in Disposable Email Addresses, WordPress.com did accept the email.
Today, I got my first WordPress.com email delivered to my BurnerMail mailbox. I lost my Gravatar but that's okay! (In fact, I think Gravatar has an option to link the same image to multiple addresses. Something to look into, later.)
I should point out that BurnerMail has two types of email addresses. The one I just mentioned is an example of an email address where I wish to receive email. The other type is more disposable: I can use that to forward email to my real email address.
If forwarding were the only option, BurnerMail would not be much help in keeping my Inbox clutter-free. Remember what I wrote about "out of sight, out of mind?" With the option to receive email somewhere else, If I get too busy to keep up with unimportant email, they are out of the way, minimizing the risk of burying important email.
If privacy is not an issue and, if spending money is not an option, you could just create a bunch of Gmail addresses.
For my purposes, BurnerMail's integrated dashboard, browser extension and extra features are worth the fee. One major feature is the ability to turn off one email address if I no longer want the content. I don't have to even bother unsubscribing! (Great for times when nefarious marketers ignore my email preferences.)