If ya get creative - lots of things ya can do with (round). Ya can cut squares,rectangles,...part circles/part square/rectangle...tighter crops(like my mirror shot). Ya can layer shots...flowers/colors....
I hope to more master my round lens. !;can even make a nice walk around lens...-I walked around Ashland OR - testing out this lens.
Guess it's not for everyone , but it's sure creative/a challenge.
So...mine is a Sunex 185 degree circular fisheye. The Sigma is even more expensive.
There are cheaper P+S options for shooting round.
I been spending too much time on buying and selling film cameras,and not enough time on mastering my 'specialty' lenses ; round and even my Sigma 8-16 on my D5100.
But these images are from my Sunex.
Enjoy ,add a round(ish) shot if ya like...Happy Day. / Larry