It's not a matter of need, it's a matter of preference.
If you ever used a gun before (and I'm sure you haven't) higher capacity magazines allow you to focus on your shooting instead of reloading all the time. Furthermore if faced by several attackers instead of one, more rounds gives you better odds of defeating your enemies. The best reason is that most shots are misses. If you are attacked by three people, and only have a six round magazine, chances are you're going to lose that fight unless you are within 6 feet of them when shooting.
So, what do you do where you expect to be confronted by 3 armed opponents?
And if you're within 6 feet an AK is the wrong weapon.
Actually many home break-ins are done by more than one assailant. The only difference between an AK and any other semi-automatic weapon is that the AK is scarier looking. Granted, it provides more accurate distance shooting, but other than that, it's simply a semi-automatic weapon no different than a 9mm or 38. I can shoot my 9mm just as fast as somebody shooting an AK.
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Actually home invasions are pretty darn rare, and AKs are sloppy as ****, not more accurate.
If somebody breaks into your home, the last thing you're concerned about is if it's rare or not. Yes, the longer the barrel of a gun, the more accurate that weapon is.
So you're assertion here is that home break-ins are rare. Okay, let's go with that, they are rare. Now why do you suppose they are rare?
The reason they are rare is because nobody knows if you have a firearm in that home to defend yourself with, that's why. If somebody is assured you are not capable of defending yourself, why would they not break in while you are there? After all, you know where your valuables are hidden at. You are an asset to the criminal. He may even use you to go to the ATM and use your cards to withdraw even more money.