There have been other ELF linux distributions that used the old version 4 C Library, and there is a beta version of at least one other Linux distribution on the internet that uses ELF and libc-5. The advantages of the ELF binary format are very technical. The most significant advantage of ELF is easier development of shared libraries. ELF also makes it more likely that different versions of the same shared library will be compatible. Libraries with different jump tables were incompatible, and often a new version of a library was incompatible with its original jump table because a variable grew in size too much.
ELF eliminates the source of incompatability by resolving symbol names at load time.
With ELF come some bonus features. For starters, standard ELF shared libraries are also dynamically loadable, meaning that programs can load, execute and unload code from new libraries while they are running. It is also possible to have extra libraries preloaded ahead of a program's usual shared libraries. Linux ELF executables will not currently run on SVR4, but a small amount of code is now shared between the SVR4-ELF and Linux versions of the GNU utilities that produce and manipulate system binaries. Bug fixes in certain areas of the SVR4 code automatically apply to Linux and vice-versa.