Most of us took up the CFA exams for career advancement and development opportunities - so did I back in 2009, amongst other reasons.
Upon scraping through the last Level III battle and obtaining the elusive CFA charter, I embarked on a job search, not because I wasn't happy with my current role at that time, but it was in response to my boss' comment during my year end review and salary negotiation that prompted me to look around to "benchmark my market value". It was an interesting exercise as there wasn't a strong pressure to leave per se (i.e. I didn't hate my job/work environment), but I was also incentivised to secure an offer for real as that serves as a true measure of my market worth (plus it was always interesting, to me at least, to find out what other roles are they out there).
Good practice for interviews? Definitely. Stressful? Certainly (the goal is still to secure a job offer!). Useful? Very, because I also got a good sense of employers' view of the CFA charter and here's an attempt to provide a qualitative assessment of the CFA qualification on my job hunting process.