Using an airsoft gun as home protection does not usually come to the mind when thinking about home protection. More traditional is a home security system or a real gun. But let's look at the negative sides of those two options (there are other things, but I'll just focus on these two). I first would like to say that the home security system is definitely the best way to go, and the only real downside is the price. You have to pay a large monthly or yearly charge in order to keep the service, and that can make a big dent in your budget. And let's be real, you do not need the actual system as long as you have the sign on the front of your lawn. If you have the money, the security service is the best route to take, but of course a real or airsoft gun could be used as a backup. The problem with real guns is that, according to statistics, they kill more people than they protect, in the case of home protection. Also, you are supposed to keep the ammo and the gun in separate places, which is worthless in an emergency. Imagine a guy waking up to a burglar, reaching for his gun, and remembering the ammo is in the basement. What a horrible feeling that would be!
An airsoft gun is the perfect alternative to a real gun. While, of course, it does not have the power a real gun has, it still is an effective defense weapon. You don't need to seriously injure someone or kill them to stop them. However, a spring gun would not do well enough, because you would need to fire multiple times. You may be worried, if the assailant has a real gun, that he would be able to defeat you. This is not true. While it cannot be argued that he would have an advantage, you can still easily "win". If you shoot someone in the face once with an airsoft gun, they will immediately reach up to their face, even if they have a real gun. It really only take shot, because getting shot in the face with anything hurts A LOT, and the burglar will be stunned for a good while (only a few seconds, but in the moment, enough). This gives you time to run up and give a hit large enough to knock him out or disable him. The airsoft method should be used in conjunction with a bat, to be sure that you completely disable the assailant. The reason you should not use a spring gun is because one, they are not that powerful and would not hurt as bad, and two, if you miss, you cannot afford to re-cock the spring.
I bet all of this seems like a lot of trouble when you could simply kill the guy. Keep in mind that real guns are incredibly dangerous, and as mentioned, hurt more people then they protect. Also, you get into a lot more legal trouble if you kill someone, even if it self-defense. Not to mention, shooting someone makes a lot of blood, and then you have to worry about cleaning all that off your wall and carpet/floor (that's a joke).
Even if you have a safe neighborhood, something bad can happen at anytime. There are times when you might not feel safe for some reason. Having an airsoft gun can make your home feel safer; it does not have the serious damage capacity of a real gun, but it will work in an emergency. On dark and stormy nights, a simple airsoft gun can make the difference between feeling scared or calm.