...thats... thats how advertising works. They're trying to sell you something by claming it will make your life better, so they tell you that your life without this product is bad. This isnt the dev-team nor is it even the people who designed those robes, its some PR-person needing to come up with a catchphrase to sell you this item - and trust me: They didnt check all the gear in the game to come up with a truthful statment.
Advertising has very little to do with actual truths - which reminds me of a story I once heard told in a podcast: A former games journalist talks about how his little daughter (maybe 7 or so at the time?) asks him about his former job by describing the magazine he wrote for as "Its like a newspaper, but everything in it is fake, right?" First her dad is irritated by that ("Our scores werent bought! We reported honestly!") but trough some conversation he manages to figure out that she isnt thinking of a magazine but of a catalogue (to order things from, those paper-things we had before amazon if anyone still remembers) - so... a 7 year old was manage to graps the concept that advertising isnt true.