The importance of your fact (above) cannot be stressed enough. That propaganda victory:
1) demoralized Johnson into not seeking re-election.
2) emboldened a Soviet invasion of Czechoslovakia.
3) emboldened the N. Korean hijacking of the USS Pueblo and the imprisoning of the crew.
4) led to the Marxist Yippy riots at the Democrat National Convention, the first step in the subsequent Leftist takeover of that party.
( Others on this forum can probably add to my list. And I wouldn't be surprised if intelligence showed that there was a link between the Tet Offensive and the Assassination of Martin Luther King and the assassination of Robert F. Kennedy. )