Guild Wars 2

I was so excited to get permafrost because the dye had so pure glowing white color at the hero panel.
So I bought the dye and found out that the dye also reflects the color of the game field to great extent…
If the environment is yellow, it looks like white+yellow. If the environment is grey, then the color is grey
There is almost no difference between “permafrost” and “white” dye in the actual game field although at the hero panel the two colors differed significantly.
The only way to see the difference is to use the color on your entire armor

So, I am having trouble in choosing between d/p vs p/p for my lv 77 thief.
I heard that d/p is meta which has highest dps, but I really don’t think so.
Whenever I see field bosses, I have to spend minimum 5 min to take down the boss when using d/p ( and very hard to control my hp ) because my main attack would be autoattack which deals like 200~300 damage.
Whereas, if I use p/p, I easily reach 10k with unload which melts down field bosses in less than 2min. ( also I attack from distance ).
And short heartseeker doesn’t work when using action camera.

I also don’t understand why people use d/p instead of p/p in WvW or sPvP. Isn’t it more dangerous to go close to warrior or guardian than worrying about reflections? All you gotta worry about for p/p is reflections, #of initiatives spent, and enemies evading.
Also, can’t p/p thief easily solo kill elementalists and other thiefs with unload?
I don’t get why p/p is not the meta.

It would be nice if some professional players give me advice