Swift: Do Classes NEED initializer methods?

Hello,

I recently finished the Object Oriented Swift course in the Beginner iOS Development track. So, I know with Structs a member wise initializer method is created for you but with a class you have to manually build one. My question is, if your stored properties all have default values, do you even need to build an initializer method? For example:

class Flashlight { var isOn: Bool = false

func turnFlashlight(_ key: String) {
    if key == "on" {
        isOn = true
    } else if key == "off" {
        isOn = false
    } else {
        print("Error: You cannot turn a flashlight \(key)")
    }
}

}

The above code runs just fine for me, but it does not include an initializer. Now look at this code:

class Flashlight { var isOn: Bool

init() {
    isOn = false
}

func turnFlashlight(_ key: String) {
    if key == "on" {
        isOn = true
    } else if key == "off" {
        isOn = false
    } else {
        print("Error: You cannot turn a flashlight \(key)")
    }
}

}

The code above includes an initializer to set my stored property. I get the same results.

Which is best practice? Should I always use an initializer? Or can I omit it in cases like this? I want to follow best practice.