I do something similar, except that I add entries to the MTA configuration to do the redirects, rather than use a wildcard. That requires positive action (adding the entry), and I don't have to worry about spammers bugging me by just sending stuff to random addresses. If I start getting spammed (and it HAS happened) I can revoke the address by just removing the redirect.

Amusingly, spam is still getting sent to some of these addresses that I revoked years ago, only to get bounced. I guess it's too much work for spammers to clean the deadwood out of their lists, especially since that inflates the number of addresses they can sell. The good thing is that these addresses are excellent spam traps for fail2ban.