Since you are a Platinum, and some of the posters above say you have an 80% chance of an EUA, I would NOT use the miles. (I personally think that you chances of upgrade are greater than 80%).

It is like buying a lottery ticket, with the great feeling of 'winning' when the EUA comes through... (But, in this case, you have such a great chance of winning.. think of how you will feel when the EUA goes through and you save the 10,000 miles... Then again, sitting in the back for 5 hours when you could of spent only 10,000 miles...)