To me, their usage is akin to to turning a plaintext file into rtf. Emojis do not look the same across platforms. Generated text should default to the generic IMO.
Plain text doesn't look the same across platforms for the same reason emojis don't, what's your point? At a technical level, it's no different than a plaintext doc with Chinese (or almost any other non-latin script) characters in it. It's still just a linear stream of text encoding with no specific structure beyond that.
