SMILES contains the same information as might be found in an extended connection table.
The primary reason SMILES is more useful than a connection table is that it is a linguistic construct, rather than a computer data structure.
SMILES is a true language, albeit with a simple vocabulary (atom and bond symbols) and only a few grammar rules.
SMILES can be canonicalised. I.e. there is a unique, universal “name” for a structure
SMILES representations of structure can in turn be used as “words” in the vocabulary of other languages designed for storage and retrieval of chemical information .E.g HTML, XML or query languages such as SQL.