And Unicode also has an emoji variation selector U+FE0F, which requests that the preceding character should be rendered as an emoji. Thus, Unicode already has a unique, backwards-compatible encoding for the Bitcoin emoji: ₿ (In the future, with a supporting font, you should see this as a Bitcoin emoji) U+20BF BITCOIN SIGN U+FE0F VARIATION SELECTOR-16

It would be considered non-standard until sanctioned by Unicode, but fonts may already be able to implement this. All Unicode needs to do is include this sequence as part of the standardized variation sequences.