Renewed Hope is the way for Vanguards to have an element of surprise. Vanguards in general are very straightforward and predictable in their gameplay.  Renewed Hope is the Vanguards’ way to spice things up, and is one of the most versatile events in the game.

Renewed Hope should be a highly used event. Its versatility is so high that it could have a page dedicated to itself and its many uses and surrounding strategies. 

But to summarize: 

It can allow you to attack with Sera and then protect her.
It allows you to place a gate in the build phase and then summon adjacent to it, allowing you to summon in a lot of places that the opponent cannot expect or prepare for.
It allows summoning adjacent to Sera on defense if cornered and on offense to keep your offensive push going. 
It allows you to double attack from a single flank, combining with a Citadel Archer.
It allows you to summon multiple units from the same spot.
It even allows you to get ahead on tempo as you can summon units after you draw them on your draw phase!

It has so many uses that it is very rare that you can’t find applicability in a game.