What statistical value is to be used for a given data depends on the application or the context.
Suppose We want to know of which age students visit most at brainly. We want to know the most frequent user age. For this purpose we will use mode. We may have multiple values of mode. Here we are looking at a small fraction of the entire population (data). We may want to do some thing for them.
For example, a chocolate manufacturer may want to find the most sold chocolate. Then do some more improvements on that. This is a use of mode.
Median: 50 percentile or expected value:
Suppose we want to know how the level of population. We look at the marks. We want to know below which mark 50% the students are. This is the level of the middle of the class. Next year we can find the 50 percentile mark. If this mark is higher than previous year's, then the performance of the class, students, teachers etc. has improved. We can say so.
Median is the expected value of the given data, a representative value for the data. Also, it is the middle of the probability distributions. It is used a lot.