The amount of effort versus what you get back are not worth it unless you have time to focus on just playing War Thunder. The special events used to be a good way to grind out vehicles, but over time became harder and harder to complete without being forced to spend money on time-savers. As I played over the years the game became less and less fun and more of a chore. The early vehicles are fairly easy to unlock but it becomes clear that once you hit rank 4 that there will be a serious time investment just to reach the next tree. Be prepared to play as 3-4 vehicles over and over until you can earn enough experience and in game credits to unlock the next vehicle. I hope that the nation you picked has a strong lineup, or you could just spend a wad of cash to buy a premium vehicle to fill out your ranks. Ha ha, just kidding.....unless?
Gaijin has a unique game on their hands with a huge list of military vehicles, but it's locked behind a horrendous grind designed to draw you in and then waste your time while promising extra benefits from cash only vehicles or subscriptions.