Objectively that is a bad idea. If foreign intelligence agencies are gullible you can downplay your military capabilities or up play your capabilities. The parades can also help to spark nationalistic pride and increase recruiting as a side. Military Parades where you stand around in the sun listening to a parade does nothing, but showing of your military capabilities to the populace can help.

The Soviets flew 10 Bison bombers over the parade six times making the US intelligence agents present think there was 600 Bison bombers and there was a huge bomber gap. The Soviets only had 23 Bison bombers.