The highlighting of the more valuable rewards had been introduced for Tyche´s Advent Calendar 2017, and was supposed to indicate that the chances of gaining the highlighted rewards were lower - in fact at that time the grade of that highlighting was the only indicator for those differing chances. As a result, many players now associate highlighted segments with lower chances.
Please also see the text of the respective changelog, clearly connecting the background color/the grade of the highlighting of the wheel´s segments with the (lower) chances:
Functionality of Tyche's Advent Calendar has been adjusted to balance the chance of getting specific items in accordance to their value.
- Every wheel contains 6 specific items that can be selected by spinning the wheel.
- Each item has a certain value, from regular to rare to very powerful. The chances of getting these items now scale with this value, giving more powerful items less of a chance of being obtained than regular ones.
- These chances are highlighted through the background color of the respective item on the wheel. The brighter the glow, the smaller the chances of getting the respective item on the first spin.
-
When the new display of the chances was introduced, the percentage shown in the respective image also reflected the connection "highlighted segment" = "lower chance", see here:
In the current event the highlighting (in the players´ heads now connected with lower chances) was retained unchanged for some reason (?), while the (even) chances indicated in numbers seemed to contradict the (lower) chances indicated by the background color of the segments. At first sight, several players even thought that this was a bug, and I know that even up to now some players do not trust in the numbers but are convinced that their chances of gaining rewards from the right side of the wheel are lower (because those are highlighted).
That´s why I would avoid any highlighting of wheel segments in wheel events with even chances - the highlighting is obsolete or even confusing in those cases.