I also received the 47.5k offer today. It made no mention of the cash option. I wonder if this is part of the survey process - if they don't get enough bites, the miles option is gone.
Unless I was sitting on millions of miles, I would never spend them this way (maybe they're figuring that out). 47.5k miles are worth a lot more on a longhaul premium award than a $375 RCC fee.