Direct symlink farm for transitive dependencies vs search paths

[amano.kenji]

Let's say that A depends on B, and B depends on C.

With search paths, A doesn't have symlinks to B, and B doesn't have symlinks to 
C. Thus, disk space is saved.

However, adding search path patches to existing softwares is cumbersome, and a 
long list of search paths results in inefficient searches.

Let's assume that B has symlinks to C, and A has symlinks to everything in B. 
This means A has symlinks to symlinks in B. Transitive symlink is probably more 
efficient than search path. If A just copies symlinks from B and has symlinks 
to plain files in B, then A ends up with only direct symlinks. Direct symlinks 
are more efficient than transitive symlinks.

It seems that search paths are preferred over symlinks to transitive 
dependencies in gnu guix. Why?