Emojis should be purely generic, and not represent an individual product or service.
No apple logo. No BMW logo. Generic.
Imagine if every brand had a fucking emoji, what a wasteland that would be. And then in years to come the unicode character space is littered with dead brands that have gone the way of the dinosaur but still living on in emoji form like digital trash, because emoji are permanent. There's no taking it out once it's made.
So I'd support an emoji to represent the notion of 'digital currency' but it should be generic, not Bitcoin.