The importance of this was demonstrated a while ago when Minecraft had a major security vulnerability. The Wurst client has been around since 2014 and is actively developed by its German creator.
We don’t support such hack clients, but we think it’s okay on private servers and realms. Maybe you belong to this group of players and want to try out the Wurst client in Minecraft. Basically, you should not hack in video games, but some players want to gain an unfair advantage for various reasons.
