I think it’s unreasonable to expect an announcement to the effect that some nice new trains are being temporarily replaced by some older ones. Simply replacing a new train by an older one doesn’t particularly inconvenience passengers, so doesn’t warrant an announcement, particularly as it’s relatively short term.
In the other hand, it’s perfectly right and proper that TfW would want to shout loudly about its new fleet when first introduced. What business wouldn’t, as one of the first tangible signs of the Metro project?
So that was an announcement aimed as much at the wider community in SE Wales that the vast amounts of public money are now producing results, as at the day to day passenger, who let’s face it would have seen the change the day it happened.