I played around with it on Ekko earlier in an ARAM to a good effect. I don't troll but i try to make underused items viable.
Again this is ARAM mind you. Im pretty sure Sona was on my team which also helped the choice of going for AA.
I have no real experince as Ekko so I just tried to play like a Bruiser, I did not really invest alot of runes or masteries in ap, and at the early game they didnt build any mr so i didnt feel like i had to build ap. I just waited for Sona to use her q and possibly e and then boom, I did E2AA and followed up with an Q and most of their team would backaway except the Zed who was a fairly decent player himself.
We ended up winning the game before 15 mins and I was starting on guinsoo's just to build him Hybrid since i have rune and mastery pages set up for hybrid penetration. I felt kind of similar to kayle but with all of the abilitys switched around or inverted to be honest but it was the most fun i have had with Ekko.
Sadly can not say about its performance in SR I imagine there are plenty of other options that maybe better for his late game. But in ARAM with Sona it was beast.