Not necessarily, but if sophisticated language comes out withouth real effort (
1)not like the reply I sent to Domenica to her request for help, she knows, er, well, she might want to publicise it, coz I think I have deleted my PM box

), naturally, I mean, then why not use it?
2)I believe that there is no rule such as "always use sophisticated vocabulary and syntax" or "always speak and write simply". Every occasion and every subject requires different use of the language.
Word hunters, you might have said

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What, in your opinion, is pretentious language?
From Russia with love, Mr Bond

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Give my regards to the babushkas

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