Next time you're at an airshow, or even better an non-aviation event that the Reds are displaying at, watch the reaction of the crowd when they're on. I was up at Dawlish for the Lancs in August, and watched it all from the steep hill to the west of the town. The public were going bananas while the Reds did their display.
The team also flew a display over Falmouth this summer, and my understanding is that the town was packed out. Certainly the words 'Red' and 'Arrows' seemed to be bandied about a lot for the next few days. Last year one of the Household regiments paraded through a local town while they were on a summer camp. I've never seen the town so busy, and the reception they gave was amazing.
No, such things will not replace body armour etc, but they will keep the military in the public mind for a lot longer after the last guys (and gals) are home from that wretched part of the world. Without the Reds, or HMS Victory, or the Household Cavalry, the ever-shrinking armed forces will become less and less visible to the population as a whole.