"Spinny" is a bit of a strange reason by itself.
If you have 50x11 (120") as your top gear, you would be unlikely to spin out.
I used to ride 54/44 for TT's when the norm was 52/42. This wasn't to give a higher top gear, it was to make the middle (16t) sprocket more comfortable. With a 52t, the 16 sprocket was too low and the 15 too high. The 54t made it just right. Additionally it made the chainline just right and gave me two higher gears, I only had 5 sprockets in those days (14-18).