I don't see any harm in it. Members are politely asked not to start multiple threads with identical content (usually done because they think it fits in two areas, and you end up with the thing being split into two conversations where one would be better, and it also annoys some people for being a sort of spamming - the thing to do is just pick which one board you think fits it best).
But adding your pics here as well as in whatever thread they were already in isn't quite the same thing as that, and doesn't really cause that problem (at least it hasn't so far). These threads are more of the nature of a slide show than a conversation, so it isn't an exact duplication. Like a kind of digest version of what has been going on the previous month. As Steve says, you might see something you like from a part of LAF you usually don't visit.
If someone does want to start a big conversation about your models here, you can always direct them to the original thread if you like. Either way it isn't really a big deal, I think everyone is pretty chilled out about it. But what does rile a small section of the membership is finding the exact same thread cropping up all over the place. To be honest that doesn't do much harm either, but it is a bit messy, and thus is against the rules.
But "What I painted in..." has become something of a little LAF tradition. We don't want to put a damper on it by saying "nyah, nyah, you posted those there, you can't post them here" and making loads of new rules to suck the fun out of it. So I would say go for it. This is just my opinion, though, not company policy.