They are called pros for a reason.
I had someone in ranked try and justify buying Tri force on ekko just because they saw a korean player do it once. Even though that gold could of been used on something like a rod of ages.
Just please, build what you know is good, not what you saw some pro build.
"I saw Pants are Dragon play lucian jungle, so it must be viable!"
Yeah, I hate when people blindly copy challenger/pro players.
Ah, the blind 
rush against a team comp that requires HEAVY scouting.
After Karma became a top pick (as well as many backline supports getting picked) in competitive so many people are going with that build on every spellthief support nowadays.
Why would you ever build AP on Ekko? He scales up so much better with raw durability. Trinity is better because it's a better single offence item, it lets him get some damage before going into a full tank build without needing to buy extra offence to supplement it.
But then they would have to come up with their own build. And that's hard. Like, thinking to not build straight off of recommended items (which only include armor, for the most part) when there is an anivia/annie/AP blitz on the other team.
