Part of using GNOME (at least to me) is expanding on the interface and building a personal experience through extensions.
Cover-flow when and-tabbing? Extension. Dynamic opacity of top bar? Extension. Wiggly-wobbly effects when dragging or minimising/maximising windows? Extension. Installing custom themes? Guess what, that’s an extension too!
I think you understand where this is going.
In terms of polish (looking sharp), GNOME is the best on linux, still it can look much better in terms of eye candy if you add extensions. I think I have like 50+ extensions myself.
It makes the OS and general interface more pleasant to look at and tickles the estethica oblongata.