I don't pick her as first heal in solo q, I insta lock moira. But I main them all, my ana win rate laste season was 80% just because I knew she was the best support for that situation.
Sometimes it's zen, sometimes mercy..
Ana is easy to dive, you slept gengu ulting in the back, calling it, but everyone ia busy not listening then he wake up and 1st thing you know, that mer y bitch dash on him and you get pick.
Ana is useful when yo need to deny. Heal or ult.
Hog and bastion or my favorite victim, close second cowboy in high noon.
Learn to flex on your support pick, it's a game changer, ana is by far my favorite support but some time you'll need mobility, heavier heal or increased damage.
gl