Realtime ranked gameplay where everything is serious and the meta is extremely prevalent allows a person to actually see what's effective on the champion or isn't.
More than that, there are advantages and disadvantages to be noted after testing and optimizing a playstyle. Most people who optimize playstyles (i.e. Dopa) actually copy them from other players, so the likelihood that we've found any "best" build for Kindred atm is extremely unlikely. You've yet to give true insights and are basing it on conjecture as the platform of your topic, which even if you do have more than conjecture, is not being showcased at all.
Regardless, I've played Kindred on PBE myself and have experience on her on live with a relatively high winrate for how little experience I had prior to picking her up this season. You can at least meet people like me in the middle instead of pass the boundary that the more experienced players have a right to cross.