The most likely use for these e-mail addresses will be to send Malware to.
For example, my spam folder in the past got multiple e-mails about replica jewellery, drugs, etc. per day.
From a quick check now, in the past 30 days (before it auto-deletes), every single e-mail claims to be a document, eFax, Amazon order, unpaid invoice, etc. all with a Zip attachment containing an infection.
In one way, it's quite handy for giving an Internet security tool a test run in a virtual PC. Just keep importing the infections over the course of the trial period and see whether the utility catches them all.
One thing that is obvious - Gmail's anti-virus protection is not as good as it was in the past. For example, there was a time when G-mail took great effort to stop infected executables getting through and blacklisted quite a large range of executable extensions even in Zip and RAR archives. Now, they seem to be ignoring .js and .docm extensions for delivering infected JScript and Macro-enabled documents which seems to be the main distribution method Malware spammers have turned to.