All .NET objects have a ToString method and many have a Dispose method.
ToString is useful on the actual .NET object on the desktop as it often returns useful information. On the device it is less useful as it usually only returns the class name for space economy reasons. However as libraries hold their underlying .NET objects (if any) as Value or ControlRef properties you can't call ToString on them in Basic4ppc except by using the Door library. The library ToString will usually only return the class name of the library object so is of little use.
Dispose, if present, is used by Basic4ppc but in general should not be used by a Basic4ppc program except perhaps on Bitmaps but now ImageLibEx makes that unnecessary.
In StringBuilder I chose to overide the default ToString to return the contents of the StringBuilder rather than the class name of the library StringBuilder object. However I didn't expect Basic4ppc to pick up the original (and I am not sure why it does) as ToString2 which just returns the class name - so no, it's not much use.
For completeness I also got the scope of the underlying "version" field wrong so it is visible to though unusable by Basic4ppc. This field is what the DllVersion property returns.