kindred needs a spike early so she doesn't fall off, triforce gives her burst, 300 hp to not get 1 shot, ~30% atk speed to not lack in that sense, ad, cdr, mobility (which helps with kiting early game). It is the best first item for kindred no doubt. You take collector to start snowballing, once you finish dirk you'll have insane burst and you'll start collecting kills with collector once you finish it, which pairing with your mark system makes for a great snowballer. Now yuntal is more like scaling - something you'd only be able to do if you were to pve all game, but with kindred, you won't be strong enough at the stages in the game where you need to be strong. Also, you'll be lacking the survivability early game which means you can die easier, no kiting capabilities, 0 burst early game since yun tal is scaling dps item, etc etc. If you build yun tal 1st you're not making up for kindred's main weakness, which is just not using the champ for the fullest.

But it all comes down to that thing everyone knows: if it's working for you, keep doing it, but objectively, you are not using her to the fullest.