Short answer: Many people seem to like a symmetrical, high & tight circumcision for its appearance, like yours. If someone finds circumcision erotic or pleasing, then some results are bound to stand out for their visual impact and it's nice to let the lucky penis owner know.
Longer answer:
What makes a circumcision attractive or hot differs among admirers. There are different "styles", different techniques and obviously different outcomes. If you get complimented on your circumcision, it probably means that someone thinks the result on your penis is symmetrical and reflects a style they find aesthetic.
When people say someone has a lot of skin left, it can mean two different things. Either the cut is
loose, so there's movable skin on the shaft when hard, or the cut is
high, meaning a lot of the lighter pink, everted inner foreskin is left. (Since the foreskin is a double layer, the mucosal inner layer normally lies forward, covering and making contact with the glans. It's not visible when a guy is soft. After circumcision the amount of inner foreskin that survives is normally everted backward onto the shaft and heals proximal to the rest of the shaft skin, at the scar.) Since circumcision can really only remove tissue in varying degrees from 3 areas -- shaft skin, outer foreskin or inner foreskin -- connoisseurs know the principal styles as
High & tight (some shaft skin removed, lots of inner foreskin left & smooth)
Low & tight (almost no shaft skin removed, little or no inner foreskin left; scar is right in the sulcus)
Loose (overall less skin removed, resulting in substantial bunching when soft)
Technique can refer to the method by which you were circumcised. Different devices can leave telltale signs. Often, boys circumcised using a Plastibell have a different, thinner scar line than boys cut using a
Gomco clamp, which crushes the foreskin and can leave a wider brown ring. Freehand and Mogen clamp also can look different. Infant circumcisions typically have no suture scars and can often be easily differentiated from adult circumcisions.
Your own skin type often determines how much of a coloration difference your circumcised penis exhibits where the outer shaft skin remnant meets the glabrous inner mucosal foreskin remnant. (Since most infant circumcisions remove some of each.) The tissue types themselves are different, but some men's natural pigmentation results in a more obvious hue difference.
Circumcision, particularly at birth, can leave unintended consequences, like asymmetrical scars, skin tags, skin bridges, fistulas or a nicked glans. The frenulum may or may not have been ablated or reduced during circumcision.
No two circumcisions in the world are exactly alike, because circumcision is an inexact procedure; it's all simply removal of penile skin. The foreskin, as such, is not a specific, delineated item like a tonsil, an appendix or a wisdom tooth. Where the shaft skin ends and the foreskin begins has never been anatomically defined, so the procedure is as much art as science. Thus, as with all art, beauty is in the eye of the beholder.