You can’t have broad appeal and also use your darling specialist phases everywhere on your site. Getting rid of jargon is the safest bet. When you use specialist phrases, making sure that the vocabulary is common beyond a shadow of a doubt is difficult or almost impossible.
Among specialists a measure of common jargon can help convey precise meaning. That’s why specialist vocabulary emerges after all. However, it should never become a way to feel smart or part of an exclusive club. Obfuscation is part of the culture of some organizations and professions. Sometimes language is intentionally difficult like in French literary theory.
When your website needs to get as many people as possible to change their behaviour, register somewhere or buy something, you can’t afford to fall back on selective and divisive language.
On the public internet you never know who is reading. You don’t have any idea of their background, reading comprehension skills in your language, etc. The copy might very well need to convert an audience of professionals. Yet, it has to convert them even if they aren’t fluent in your language, if they are rushed and stressed, if their kids are yelling in the background or if they’re having a bad day.
Using plain language is important. It doesn’t have to make you sound like an overly familiar simpleton. Within plain language, there is a lot of room for nuance. You can even achieve a formal and academic tone without using jargon.