That is for Bitcoin, not for sats (as they want to use it).
⚡️ is for sats, because mostly we use them over LN.
The unit of account is sats not bitcoin ₿
Discussion
Is that true? More LN transactions take place than sub 1 BTC on chain? The dollar system uses $0.75 and 75¢ is the unit if account the dollar or the cent?