I used to be able to get text from a Word doc (copy it), and then go into my CS4 InDesign file and paste it into a waiting box that had a paragraph style assigned to it and boom, it would take on the assigned paragraph style of that text box. Now it brings in the style from wherever the text came from. If the font looks similar to what was there it can be too hard to tell that it's different. When you are working on a book with 200 pages and copying text from Word docs and dropping it in here and there in InDesign, it causes alot of extra work and problems.
In fact I have lost alot of security functions I used to have in CS4 in CC2014 in InDesign, Photoshop, Illustrator and Acrobat and it is making me want to go back to CS4 in a hurry.
Pasting styles or not is a preference item.