It has proven to be so useless, that it only is used to watch YouTube, NetFlix, and surf the net. "Dad! I can't add iTunes! There is not enough memory!, I can't play games! There are no Apps!". *sigh*
You do realize that Chromebooks and Windows Laptops/Macbooks aren't even supposed to be comparable, right?
Chromebooks are designed with the most basic user needs in mind.....the internet. Most people don't need super powerful machines that can run super powerful software for things like photo/video editing or gaming etc, etc. They want facebook, amazon, ebay, netflix, youtube, email, and maybe google drive. That's pretty much it. If your needs exceed that, then no, a chromebook probably isn't for you. But if you're just a regular schmuck like most, then a $300 chromebook is a far better use of money than a $1000 macbook or windows laptop.
As for the lack of iTunes, well, duh. Google does have it's own ecosystem similar to iTunes though. And with Google Play Music you can upload your entire iTunes library (up to 50k songs) for free and it will maintain your playlist integrity. Now your music is safely stored in the cloud and is available everywhere you go. You can also download your music back to a physical drive whenever you want.
Also, there are plenty of apps and extensions available in the Chrome Web Store. But if those don't quite suit your needs, a few 2016 Chromebooks are capable of running Android apps from the Play Store and I believe all 2017 Chromebooks will have the same capability.
Personally, I think chromebooks are exactly what the market has been lacking for the last 20 years. The only thing that was really holding it back was the lack of a developed cloud system for storage. How many people out there have dropped thousands of dollars on PC or Macs over the years and they've never even come close to using them to their full potential? It's like buying a tractor-trailer when all you need is a station wagon.