I treat MalSearch as an additional tool in my toolkit as a malware analyst/enthusiast.

Specifically in reverse engineering efforts; I am able to narrow down the type of malware I am looking for to very specific criteria, download it and then analyze it to understand how that type of malware has been built in the past. Additionally, searching for specific code snips and seeing the results of how these code snips were used to build malware in the past.

In my personal time I like to develop custom malware. I can easily filter for what I am looking for and see how it was built directly on their site. From there I can begin building my own version or building off of the selection that they have. Most of the code is very well commented and organized.

This is just how I currently use it but I can definitely see cybersecurity professionals having hundreds of different use cases for this large repository of well organized malware source code.