Finding an ample evidence in my personal experiences and observation over 71 years, I shamelessly believe in something like Law of Attraction. I believe that attitude can go as far as make a difference between life and death - from examples of some terminally ill folks who got well by changing their outlook on life; or some others who dug their early grave by maintaining a grouchy and miserable disposition.
So yes, definitely, our positive attitude shines through everything we are and we do, and on some invisible quantum level - where everything is interconnected - attracts to us desired outcomes. Even without going into that proverbial "rabbit hole", at a very superficial level we run much better chances of getting a job with our charismatic "vibes", or that special "something" that makes us stand out in the crowd.
Employers like to have a positive person on board who will pickup the mood in the work place and increase production. No one likes a sour face that's bound to drain energy out of everyone around. It's particularly true in salesmanship as well as in all levels of team work.
Actually, it's hard to say where attitude is more important. It is not only that attitude affects others, but also enormously liberates our creative potential and opens the valve of our zest for life, enhancing our ambitions to advance ourselves and succeed.