Spammers don’t bother scanning domains as much nowadays. They used to watch domain registration then spam addresses like admin@, contact@, office@ etc. but nowadays most people aren’t dumb enough to use those anymore. So spammers would rather buy a list of millions of addresses that someone else obtained by breaking into sites like Yahoo or LinkedIn, which are much more likely to be valid addresses.

You can get bitten by catch all if someone who knows you and knows your domain and knows you have a catch all has it in for you and subscribes addresses at your domain to mailing lists and other spammy places. 😊