The way I look at it, all of it comes down to what works for the consumer.
For me, I spent a lot (A LOT) of money trying different models of e-cigs. I have various 801's, 901's, 401's, 402's, and 510's. I have a DSE601 pipe. All of these, regardless of the brand or the supplier I purchased from, can be traced back to a select few manufacturers in China. And all of them have their problems.
So, we're talking specifically about batteries and the cases that house them. Each one of the 'mods' that are mentioned in the original post address one thing in common: the poor quality of the Chinese manufactured e-cig batteries. And it is a real, hard fact that these devices provide a more consistent vaping experience than the Chinese counterparts.
But each one adds a little more to the equation than simply changing the housing. Adding a manual button to better control the experience, extending the battery capacity to extend battery life between charges and provide more consistent voltage to the atomizer, upping the voltage to the atomizer to increase vapor production, making the device modular to accommodate different atomizers, closing the battery system to handle juice leaks so they don't ruin your batteries, etc...
So, in reality, none of these devices are simple battery boxes. They all add more to the total experience than just a different way to hold batteries and apply voltage to an atomizer. So, I believe the OP's original opinion holds no water. It doesn't matter what the consumer's feeling is about the device, facts are that they do more than just change how the batteries attach to the atomizer, they are more resilient than the Chinese made batteries, and are well worth the money that is being charged for them.
Of course, this is just my opinion, and I'll probably be proven wrong somehow in short time.
Ivisi