She is a good healer, and can survive longer on the field thanks to her buff, but is that enough compensate her lack of DPS or other general utility? She still has rez, which is a factor, so maybe?
Rez is good, being able to push a DPS through a fight is good. 60 HPS pocket on somebody while Ana is pumping up your tanks is not something fun to deal with. Only issue is she's really prone to dives and you are putting a lot of resources into one area. It's not a terrible strat though. Back when ult economy was a thing you could cycle her + Ana for some dumb shit; the only reason you didn't see it was that Lucio/Ana was dumber.
Also, Zarya seems to be overall buffed this patch so there's another fun thing that happened.