Well, not always. Per Webster:
1: the technical terminology or characteristic idiom of a special activity or group
2: obscure and often pretentious language marked by circumlocutions and long words
It would be great if it were only (1) but I’d often (2)
In some cases yes, but the majority of the time jargon is primarily used as a shibboleth to establish group identity, camaraderie, and a sense of exclusivity.
Even there, however, the line blurs. That is, you have terms with legitimate use that were poorly chosen. Sometimes the poor choice is historical accident, but often it's motivated by a desire to sound more impressive and complicated that it is. Something like "applicative functor" might fall into this category.
But jargon does have value in communication where you know the person you're talking to understands it at the level you do. Jargon, when used well, can let you be simultaneously more precise and more terse.
Think about times you've sent email or even just chat messages to different professional audiences. You're probably going to use different language when talking to a manager vs. a sales person vs. an engineer. I'm not talking about level of formality; the actual language you use to describe the topic at hand will change. Some of that will be a matter of the level of detail you provide, but some of it will likely include jargon (when you're conversing with someone in the same "group" as you), and you might not even realize it.
Wherever 1 or 2 applies just depends on how used you're to the usage of said jargon.