I know there's a gazillion useless Modern Store apps, but there are many very useful ones. Been watching them maturing through time since introduction in 8RP early on, especially the default MS installed apps such as Mail, Calendar, People, Weather, OneDrive, Windows phone, etc. Admittedly they were awful at first, but was mostly sparked my interest as to their purpose.
Have you used any on a daily basis to know how they work in conjunction with one another? They have matured more so with the introduction of the new Store in windows 10. There are indeed a lot more “bells and whistles” to them. Their layouts, looks, and navigation are much better.
Applications = Awesome
Apps = Crap
...Application software (an application) is a set of computer programs designed to permit the user to perform a group of coordinated functions, tasks, or activities. Application software cannot run on itself but is dependent on system software to execute. Examples of an application include a word processor, a spreadsheet design and management system, an aeronautical flight simulator, a console game, a drawing, painting, and illustrating system, or a library management system. 
backup by there definitions.