Is the adverb "ever" in the following sentences necessary or redundant?

I was wondering whether the connotation in the following sentences would change if I omitted the adverb "ever".

"Swans are the most beautiful birds that have ever graced the Earth".
"Swans are the most beautiful birds that have graced the Earth".

"He was the vilest man this country has ever seen".
"He was the vilest man this country has seen".

"He was the wisest ruler that has ever sat on the British throne".
"He was the wisest ruler that has sat on the British throne".

"The blue whale is the largest animal that has ever existed".
"The blue whale is the largest animal that has existed".


In essence, I know that "ever" functions as an intensifier, but I am uncertain if its omission/ inclusion changes the actual meaning of the sentence (I am specifically concerned about the sentences with verbs in present perfect tense and adjectives in superlative form).