This Featured page is made with the standard Gridder Layout - Video and text elements, no Fullscreen slider or Carousel is present.
You are right that the Carousel and Fullscreen slider share many similarities, however the important difference:
With the Carousel you place content into a 'Slide' this could be some text - A video etc. These 'Slides' get made into a 'Carousel' or Slideshow that you can swipe through - An important point is that the carousel can be any size on a page.
With a Fullscreen slider the 'slides' if you will, are made of the Rows in your Gridder - E.g 8 rows = 8 slides
There is more ability to create interesting layouts for your individual slides because it takes from the row. Whatever is added to your Gridder Row becomes the Slide.
Of course the catch is that it is always Fullscreen and you cannot make many 'Fullscreen sliders' within the same view screen
( technically you could but this would require some deeper coding )
Hope this clears things up @Giakonkora :)
If you have any further questions let me know and have a wonderful day