Disk space, perhaps, but Busybox was really about saving RAM space - so even today, that's memory that's available for client state tables, and that's all good..
And I'm of the old school that "the fewer features you have, the less code there will be, and the less likely it can break (or develop security issues as people start poking at it with very sharp sticks)".
Personally, I'm increasingly frustrated with modern software, where many software codebases have grown unmanageable due to including an endless list of features that nobody really needs - all for the sake of justifying continued development, and appealing to the 4 or 5 persons worldwide that might have a legitimate need for those features.