It is frustrating that when it comes to range, you always have to start by eliminating any discussions with falsely educated folks, who happen to write newspaper articles about 7 octave ranges, and somehow are able to get that crap printed.
It is beyond me, how a newspaper of reputation in other areas is so negligent in the area of vocal performances, that such an article makes it, even when it is only their online magazine.
If somebody tried to write an article in politics and would neither know states nor candidates correctly, would talk about past elections and be 20 % or 200 % off in the results, and mix up local races and federal races, and house and senate, you think, that person would be able to place their article? Obviously not.
I think, it is a total disrespect to the arts, to publish such complete garbage. The level of misinformation is just mind-boggling. And that is, as others already said, one of the objectively measurable parts of vocals.
Now I do think that range matters to some degree. If a typical more complex song is 1.5 octaves, then a person who has only 1.5 octave range, needs to sing this song in exactly the one key that will allow the person to fit it within their vocal capabilities. The SSB for instance has a 1.5 octave range, and so most people will find, that if they start it too high or too low for their voice, they can't reach certain keys.
Now for most people, once their own range is determined, it is quite normal that the two highest and the two lowest keys of that range, don't sound the best, or even worse, one key in the middle does not. A person with only 1.5 octave range, cannot avoid those keys, and that is why you often hear:
Oh
say can you see.... (with the word 'say' almost disappearing or being sung wobbly)
and at the end...
O'er the land of the
freeeeeee....(the word free sounding sharp or not pleasant).
A person, who has a three octave range, can place the song comfortably in the middle, stay away from any outside edges and other problem zones and has multiple keys and thereby choices to sing the song in. A capella, they can pick whatever they like, but once you sing with a band, then you need to sing the song in a key that is manageable for the instrumentalists. And it is also supposed to sound pleasant when all parts come together. So, then having half an octave of possible key choices while still staying away from the weaker bottom half octave and top half octave, does become a quality that matters. The reality is also that not all keys sound the same. On instruments it does matter to pick a key that sounds good for that song.
Therefore you will find, that people who have only limited range
a) sing only songs specially written for them or that are otherwise easy
b) cannot sing with instrumentalists, who have a lot of artistic ambitions themselves, and obviously
c) will use autotune a lot (and yes, they autotune their microphone sound too, to improve things a bit during live performances).
So, range gives you choices, gives you freedom, gives you the ability to do with playful ease, what others have to strain to do, and in that sense it matters. Of course, it also gives you more flexibility in song selection. You may not want to do a certain song for many other reasons, but at least range does not become a limiting factor. And all this is also why all the great singers in either rock or classical music happen to have a range that is larger than 1.5 octaves. They need it.
That said, at about 3 octaves all these benefits will start to level off. Having more range than that, becomes a game of 'mine is bigger than yours' without any redeeming additional value. I also find that outside of uneducated editorial staff of a certain magazine, otherwise this range comparison game is mostly played by fan bases, and usually the less musically inclined, play it the most.
Range is of course only one factor, when it comes to vocals. Breath control and support, dynamics, strength of the voice, beauty of the voice, rhythmical skills, a good ear, a smooth transition from chest to head voice, all these and many more will matter, to form an overall impression of a vocalist, and Cassie has explained that hundred times better already and I love to head over to the vocal materclass thread on a slower day and read a little.
Thankfully, with Adam we have nothing to worry about and everything to enjoy, whether some journalists get it or not.
