It’s just the latest catch-phrase that non-secular Protestants use to try to distance themselves from Protestants that they don’t agree with.
A generation ago they called themselves “Born Again” and many of them voted for a peanut farmer who called himself by the same turn and then they started abandoning that term.
They’ve used many such terms over the centuries as they continue to disunite with each other.
It’s virtually meaningless, then.