Every profession has terms that are specific to it. Jargon. Jargon within the profession can have a clarifying effect and can often be a shorthand for more wordy concepts. So jargon has a worthwhile effect WITHIN the profession where everyone understands what is meant.
A profession’s jargon when used with the public or with clients has the opposite effect - obfuscation, confusion. It doesn't matter whether you intend to make it difficult to be understood, or if it is unintentional. The result is the same. You have chosen (intentionally or not) to rely on the authority of your role as a specialist instead of making yourself clear. I think that this comes across as arrogance. I think it is another way of saying, "Just trust me." Trust is earned, jargon gets in the way of trust.
Everyone has experience with obfuscation. You are in the minority if you don't find it at least annoying.
Why would you choose to NOT be understood? I can think of one or two scenarios, but they are outweighed by many more that are not very attractive.
What if you think in jargon? Well, that clears up your motives for using it, but you are still left with poor communication and lack of understanding.
Whenever you need agreement, jargon works against you. Even if you get the agreement, the client has an escape hatch - "I didn't know that's what we agreed to" or "I don't remember discussing that".
You can tell that I am not a fan of jargon. I don't think it is just me. If it sounds better when you use jargon, I think it is because the jargon conceals the weakness of the idea(s). Do we want weak ideas? I don't.
But let's go back to the trust issue. I have heard it said that there are two things you must demonstrate to win a design job - technical competence and trustworthiness that you will deliver on your promises. For many clients judging technical competence depends on past experience. Have you done this before or not? But all clients can judge trustworthiness. They do it all the time. So I think jargon lets you down in the exact scenario where you are really depending on it to make you look like a good choice.
Lack of understanding (jargon) and trustworthiness travel in different circles.