I would add that gabions being "loose" have an additional usefulness as they are very flexible and allowing differential land movements (which are often the cause of cracks and instabilities in more rigid structures) and are thus a good anti-sismic structure.
About duration, at least here (Italy) they are usually considered in the 100 years duration range, not unlike many other kinds of structures.
The inherent draining is the clearest advantage when compared to other solutions (make sure to use some geotextile behind them to "filter" small particles) , though - to be fair - they do need more space than other kind of walls and they rapidly become unusable when you go over 3-4-5 meters height.
About duration, at least here (Italy) they are usually considered in the 100 years duration range, not unlike many other kinds of structures.
The inherent draining is the clearest advantage when compared to other solutions (make sure to use some geotextile behind them to "filter" small particles) , though - to be fair - they do need more space than other kind of walls and they rapidly become unusable when you go over 3-4-5 meters height.