The two principal reasons that one might buy a luxury watch are precision and prestige.
Where precision is concerned, these watches are made to the highest standards. Though they oftentimes have a great deal of work put into the design of the watch, they also tend to have as much thought put into the movement. Constant innovation has made movements ever more precise and, because of that, these are reliable and accurate timepieces suitable for any task, even when that task might involve navigation and other endeavors that rely upon to-the-second accuracy.
Presige is the other significant reason that people seek out these watches. A combination of the practical and the indulgent, luxury watches make a statement that jewelry simply does not. These are not entirely ornamental items and their precise functions are as much a part of their appeal as are their looks.