It alerts (likely even sells) the telephone numbers of those that answer to other telemarketers. ie; it doesn't have a voice message to leave or sales pitch to attempt, once the call is answered its duty is done.
Get calls regularly from this number. Will block as soon as I figure out how,,lol. Scammers for sure. I just answered another one but I don't say anything and then they finally say hello, hello,,,then they hang up. I just LOL at these [***].