When a group of people talk to each other a lot they develop terms that they can use in place of larger concepts. This makes it easier to talk to people inside the group, but then it's harder to talk about the same ideas with people outside the group. If we were smart enough to keep up fully independent vocabularies where we would always use the right words for the people we were talking to, this wouldn't be an issue. But instead we get in the habit of saying weird words, and then when we want to talk to people who don't know those words we either struggle to find words they know or waste a lot of time introducing words. Especially when the group jargon term offers only a minor advantage over the non-jargon phrasing I think this is a bad tradeoff if you also want to speak to people outside the group.
Recently I've been working on using as little jargon as possible. Pushing myself to speak conventionally, even when among people who would understand weird terms a little faster, can be frustrating, but I think I'm also getting better at it.
I also posted this on my blog
Part of being an effective communicator is optimizing what you say for your audience. You shouldn't take pride in not trying to do this. Train your brain to make optimal use of jargon given your audience, not to minimize your use of jargon.
New college professors often have trouble teaching "down" to the level of their students, but the solution for them is not to lower the complexity of their conversations with everyone, but rather to train their brains to respond differently when talking to students as opposed to colleagues.
This seems nonresponsive to jkaufman's stated reason for trying to minimize jargon instead of using it optimally, namely this: