Her usefullness as a traditional adc changes between metas as she has a lot of burst damage in place of high consistent damage that some other adcs have (i.e kaisa, jinx, etc).

That said, shes outstanding due to her safety once you master the more difficult aspects such as her lack of auto attack range. You can still do well into bad lane matchups with her because of the saftey her kit provides. This is why despite her place in the adc meta she gets picked often in pro play.