To be precise, there is no hard and fast rule about it. It all depends on your choices and wishes. However, it isn’t necessary, but might be a good idea if you are passionate about guns and ammo. In the military and special forces, they teach even those who have never shot a firearm to shoot with the same weapons they will carry in combat. But for civilians and the general public but there are other ways to make them learn to use a gun and those methods can be very much efficient and fun at the same time.
The most important point that stands in support of teaching people to shoot with air rifles is that you can learn all the fine points of marksmanship first. This will help you to focus on developing your skills without simultaneously learning how to operate the regular firearm. Things such as becoming used to noise and recoil, and other factors which be under your expertise quickly. After equipped with all those basic skills, when you are trying your hands on the cartridge firearm you will be a quick learner as you already know the basics. It will be just like transitioning to a new type of weapon and nothing more than that.
For example, many people learn first with an air gun, then a .22LR, and then with full power cartridges, a training technique that is proven to work well. You can also follow the order if you want to be a quick learner.
Coming to the cost, it is also very cheap to shoot an air gun and a .22, as compared to rifles, and since it will take you around 500 rounds to learn to shoot well. And thus, you will be saved from spending a huge amount of your cash on learning how to eject bullets properly. If you start with developing your marksmanship skills, maybe with an air gun, you will eventually develop quality shooting skills to flaunt.
Whether you will use an air gun or not depends on your priorities. However, if you ask us, we would tell you both yes and no. Yes, if you want to understand the nuances of holding and aiming in a less demanding circumstance, at a cheaper cost, and at the ease of your home or terrace where you are completely free to start and end as per your wish and fire as many shots as required. Also, do ensure that all the required safety aspects are taken care of.
No, if you have found out that you are good at target practicing and can do well with guns and ammo. And if you are short of budget, we recommend you to buy the rifle that you would be shooting instead of spending on an air rifle. Better go with what you want, because although it will take some more time, you will eventually learn all the skills and can become a pro at target shooting if you want.
So, all it depends on you and your condition and the decision that you will take will surely the best for you, no matter what others say.