Why use InDesign over Photoshop?
Because you have many options to work with text not available in
Photoshop for example. Because you can build very easy animation in
InDesign, because you can import Word, Excel files in InDesign,
because you can build Index in InDesign, because you can set email
and web kinks in InDesign, Because you can create table of content
with few clicks in InDesign... There are 1000s other because but
generally Indesign have too many advantages when working with
publications like manuals, books, newspappers, when designing
flyers, brochures, apps for mobile devices and so on.