Hi Karina. I must have missed it but I didn’t see what certification you were asking about. However, based on the answers of other posters, I’m assuming you’re asking about bellydancing – correct? If so, my response would be that having this ‘specialized type of certification’ can help set you apart from other group exercise instructors and thus perhaps make you more marketable to local gyms. If you love it, do it! Your passion for it will come through in your interviewing for an instructor position, as well as in your teaching.
My girlfriend loves bellydancing and I even enjoy it myself lol. It’s not just a passing fad because it’s a fun and effective activity and doesn’t require much to get started. I think it is fun because it’s unique and exotic for most participants and that’s why the best bellydancing instructors will bring people together and succeed with them.