Because right now the only options in Strike are to receive those payments as 100% sats or 100% dollars. This would allow someone to immediately have some of those tips available as cash for spending and the rest saved in sats without the user having to initiate a buy or sell transaction. I'm thinking of scenarios like these live streaming v4v shows, where an artist may need some of it as cash to send to the bank for expenses, etc, but they want to save the rest as sats. Right now that has to be done manually by the user and they will have to deal with buy/selling bitcoin.