The reason I think a Top Search is beneficial is it allows developers, such as myself to write applications from the point of view of current popular artists instead of equality, which I agree does sound unfair.
The problem with using releases is this may not take into account artists who've become popular very recently and have a short back-catalog.
For me trending is a primary business case when researching music, as it allows me to understand the artist and the modern-era.
Billboard has a great example of this:
Also this allows the user to search a modern era by letter, which is perfect for building routines like predictive search.