Would you be able to show us a photo where the watch face has a white, or light background, so that we could see the bezels? That would clearly show the similarity in display areas of the two watches.
As to the original question, the key is not one's wrist's circumference, but the wrist's width! DC2006 has the right idea. It's how much room the Watch takes up across the wrist that matters aesthetically, not the circumference!
People with similar circumferences can vary in the widths and depths of the wrists — wide, thin wrists and others narrower with more depth.
One also has to account for how much, if any, the clasps extend beyond the watch itself on both sides— e.g., the Sports Loop's elliptical rings.
So, a 45mm Watch with, say, 4mm extensions, would amount to 53mm total. With a wrist of 55mm, that would a scant 1mm on each side.
As many have noted, the other big factor is eyesight and how big a display one wants or needs. But, even there, you can lift the Watch closer to your face to see it better. Oh, finger size matters as well — could be harder to tap or type with smaller display and bigger digits!