It is more about the paste; typically you may copy the formatted text but use Edit > Paste and Match Style (Command-Shift-Option-V) to paste without any extra formatting.
In both cases( plain or formatted ) if you only select the text element and not the text.
When you paste you will get the outerHTML of the element object
formatted innerHTML element selected instead of text
Should match the style you are pasting into.
But if you pasted a formatted version you will still get formatted text i.e line breaks but the text font will likely be the main thing to match.
Line breaks will be honoured as the original format and not as plain text with no formatting