Yes, it is.
Again, it’s not ‘as important’ as it used to be. Back in the OW1 days if you didn’t counterpick you could be accused of sabotaging your team. Blizzard changed things up with OW2 and made counter-picking less critical, meaning if you prefer to play D.VA you can play D.VA all the time and you won’t experience many issues. However, other heroes will still have advantages over yours thanks to their kit and players WILL use that against you if they’re so inclined. Hitscan heroes like Soldier: 76 countering Pharah is a good example.
Meta has always been a thing, so I’m not referring to that honestly. The meta changes whenever a new hero gets buffed to the point where they’re considered OP, but counters to those heroes still exist and players will absolutely counter-pick you from time to time.