Are spam magnet addresses worth it?

It’s a common practice to maintain email addresses such as [email protected], [email protected], [email protected], etc., addresses for Internet email domains. The theory is that these provide a generic address which can be used to contact a company if the sender doesn’t have a specific address to use.
The problem is that these addresses are what I refer to as “spam magnets.” These, as well as emails which are [email protected], are likely targets for automated spam generators and, in my experience, in excess of 95% of the messages sent to these addresses are junk. Despite using a variety of spam filters, including SpamAssassin, GFI MailEssentials, or GMail‘s, Outlook‘s, or Thunderbird‘s built in junk email filters, they still get swamped.
At the domains I control, we are removing these addresses altogether, and replacing them with “less guessable” replacements (like [email protected], or [email protected]) to make them a little less obvious. Overnight, the difference is noticeable.
What’s your opinion? Is there any value in maintaining these addresses anymore? Do people still blindly send email to these addresses, or has their usefulness fallen by the wayside?