Masafi is a UAE based drinking water supplier. There has been another brand (Al Ain) which has started the "zero sodium trend". But what I have to give to Al Ain is, that they just advertised their water what it is: zero sodium. They didn't implied any health benefits or anything else. I found that pretty smart - as a lot of people are concerned about their sodium intake - hence they are "playing with the perception" that the water "can help" to reduce the sodium intake, without being misleading.
Masafi though is definitely misleading. They suggesting, that their water actively helps to maintain a healthy sodium intake. Why is it misleading? Because it all depends on ratio. Look - the recommended sodium intake of a normal adult is 1,500 mg (1.5 grams). The sodium content of "normal" mineral water is about 3mg to 33mg (latter is already pretty extreme- it is Badoit sparkling water with one of the highest sodium content of all commercial mineral waters). Compared to this, one (!!!) portion of a medium portion of French Fries has 210 grams!
Hence if you are drinking normal still water which might has anywhere around 10g or if you are drinking a 0 sodium mineral water, it makes not much of a difference...
I don't say here, that you should not buy a zero sodium mineral water (people like me, who grown up with tap & spring water from e.g. the Alps or other mountainous areas, will probably steer towards waters with higher mineral content, as low mineral waters taste kind of flat). But I say this: saying, that you have one less concern if you are drinking zero sodium mineral water is strictly a lie.