I recently got a new job title. I do exactly the same work, but the description has changed. But, I'm not saying job titles aren't important, at least not in a large organization.
Job titles are important for initial contacts. Generally in a meeting of people from different companies or teams, you start by going around the table and giving name and title, sometimes some more details. It's not about finding out who the "big guys" are, but it is useful to know: "Okay, that person is probably the technical expert", "That one is probably the contact for process stuff" etc.
I used to not care about my job title at all. I proudly answered every query with "I am a programmer." About a decade a go I was at a company that went through a layoff and a series of massive re-orgs. The entire upper and most of the middle management disappeared over night and we had an interim CEO and almost no other management. I stepped up and began to manage one of the development teams. I got raises and got to attend all the planning meetings. But I didn't change job title...I didn't care. Until, that is, they installed the new management team. The new management team dug out the old org chart and started making work assignments and decisions based on it. They brought in a new guy to be the dev manager. They literally did not know there was already a dev manager for the team. It worked out, but it was a little weird for a month or so. They learned the difference between the recorded org chart and the "real" org chart, and I and several others got "promotions" and went on about our business.
This is all leading into another post. I read lots of MS blogs, and I wonder what people outside think about how the company is organized.