Are there other merits than availability of literals in C?

It seems like one of the worst data structures ever - lookup complexity of a linked list with a expansion complexity of an array list with security problems added as a bonus.

It's fine as a serialization/deserialization primitive for on-disk files, as long as the NULL character is invalid.

String tables in most object file formats work like that, a concatenated series of ASCIIZ strings. One byte of overhead (NUL), requires only an offset into one to address a string and you can share strings with common suffixes. It's a very compact layout.