Most everyone has had at least one interview in their life, many having had a plethora of interviews before they're even an adult. Of course, there are different types of interviews. The undemanding job interview when you're sixteen and it's more of, "What's your name, birthday, and when can you start to be put on the schedule?" Secondly, the somewhat heated interview applying for a position over the phone, where you're asked "how would you handle..." and "describe a time when..." type questions, which you can usually elaborate some quick responses to respond. Then there's the interview, the salient one, dressed in the grown-up clothes that you head into knowing it will definitely impact your life or seem to make or break everything in which you've been working towards.
Interviews are a great way to see how a potential candidate represents themselves; whether their hair is brushed, if they're wearing a clean set of clothes, their timeliness, and ability to respond to questions on the spot. All employers want candidates who are strong in these areas, although, they have too much influence on who receives the job.
I've seen times where there's someone being interviewed who was on time, dressed professionally, had an outstanding resume, and a profusion of anxiety. In contrast, I've also seen someone show up a few minutes late, have a crinkle in their suit, a sufficient but not exemplary resume, and can give answers to every question asked that sound really nice to the ear.
In both these scenarios, it depends on the employer and what they value more. In reality, it's hard to say which candidate would get the job more often. Although, the candidate who is more promising, but also crippled with anxiety as being someone who gets nervous in important situations, is still hurting themselves by doing poor at the speaking portion of the interview. This one interview can make or break it all.
Not to say that interviews should be done away with, they are still very valuable. As someone who has their fair share of interviews in nearly twenty years, it does get easier. Although, I don't believe any amount of preparation ahead of time, anxiety medication, or realization that this is your fifth interview in your life and none have ended horribly yet, will change the fact that many others and myself, will not be able to show our full potential through an interview, and that someone better at answering mundane questions on the spot, is more qualified than us with interview anxiety are.
So dear future employers, those of you who currently reading this, who will be in a position of power one day, interviews are not an unrivaled indicator.