Depends on what do you want, if you expect to be a warrior yes, if you want to be a guardian WvW is fun.
I make just 5% of the kills that my grenadier engineer, but is not about this when I play guardian, is about "Protect my own" like Logan said.
Permanent swiftness to allies, aegis them, block incoming projectiles and mights (empower) is what give us power.
True people will not see/appreciate you, doesn't matter, we have a trait named "altruistic"

)
As main weapon I always use Staff being a healer/tank , secondary :
- for small combat encounters when I need to make some damage too GS
- for defending walls at big zergs scepter (to score some kills too) And for its root
- when need to protect from heavy incoming projectiles/players use any wp with a shield
- when tanking in small zergs using Hamme (good for root and holding down fugitive enemies)
Utility skills
- wall of reflection - pur fun, esspecially combined with
Line of Warding in the correct scenario you can change the battles heading.
- Stand your ground - usually when players get pulled they die, is our job to stop this
- Retreat or Sylvary root
Last example of pure fun (too bad I didn't record it) : Heavy attack on our castle, drop down to front gate, hit wall of reflection, run inside, eating popcorn while watching lots of white numbers on screen

Wall of reflection is again best used when the visibility is poor or to protect the a flank.