Apple’s iTunes and Macbook App store.
These 2 places are the same but different. Different but the same in concept. At this point i am probably not making any sense. That is unless your eco system is all Apple. The difference is what it provides for you and your specific device.
The iTunes store provides you with music, movies, apps. This option is works for all devices except the apps which will only work on your portables. MacBooks and iMacs and the mac mini have their own app store. Which provide you with a bigger scale of the programs you may want. For example: Microsoft word on your iPad is designed for your iPad. You might not get the same bells and whistles that you would get with the desktop version. Things are more scaled to the platform they are going to be used on. So if you need to buy media and so on, You can do this through iTunes on your macbook and if you need a program like iMovie you can find this in the App store.
Here is a video showcasing the difference between the two. As you can see iTunes only shows 2 tabs. iPhone and iPad. Most of the apps and games in the iTunes library cater to those 2 devices. Now you can buy music and movies and still see them on all your devices which are linked together. Assuming you use the same Apple ID across your eco system.
So remember iTunes can hold all your media. Apple store is where you buy your software for you desktop devices or MacBooks. If you have any suggestions or comments please feel free to email me. firstname.lastname@example.org