It’s really nearly all about perceived intentions towards a person, you can break things down to this basic thing when it comes to communication/interaction which includes also brand perception.
Don’t use jargon or internal terminology no one except insiders will understand when it comes to copywriting for your website. Good, clear, easy to read copy is good for your audience and therefore it is good for your business – simply because simple, plain language means your site, app or product is talking „human“.
It increases a) the readability and also b) – which is really important – the credibility because the usage of plain language is perceived as being transparent towards others and not hiding behind a hard to understand terminology which may be perceived as a sign to be more skeptic towards you, thinking even you may have bad intentions towards your users. („What are they trying hiding from me? / Don’t they want me to understand?“ )
Watch a good video about this topic here:https://www.youtube.com/watch?v=bAvW1A7UiYM