Having an altcount, whose associating is public knowledge, kind of defeats the purpose of having an alt account. Exceptions would be admins/mods who use a known alt account when they want to access the forum through a less-safe device.
The other exception is to bypass your ignore list. I use Jet Cash to look for information, and to hunt for posts to reward with merits. If someone is a merit cheat, then I don't want to reward him by accident.
Talk Merit is used when I'm in a good mood, and I am prepared to read the merit hunters threads, and most of the posters in those are on ignore in Jet Cash. I live in hope that we can convert a few of TMAN's pajeets into good posters who will contribute to the forum.
It does split your potential to earn merits though. So anyone who is desperate for merits should run with a single account. Exchanging merits between alts is public knowledge, and it will get you red tagged.