At the start of the summer, I was all for dropping Watson. Since then, everyone but the selectors seems to have dropped him, but I have to admit that he has been better than I expected, with the bat, even the ball, although not in other respects.
The most recent dropped chance allowed Watson to bring up the Australians' first Test century of the season. Much too much has been made of this. Centuries, or the lack thereof, shouldn't take on this much weight. Australia shouldn't be bothered by scores of two decimal digits except to the extent that the underlying problems are the same ones that lead to scores like 150 all out.
It may not always hurt to play for a personal or even team milestone, but there was nothing good about the situation as Watson was restrained in the 90s. The team needed relatively quick runs, not landmarks, and cricket is a team sport.