Yoga is a personal and intimate experience shared with like-minded others also seeking inner peace and development, so it would make sense to share stories of how yoga has changed their body or their life. People are always touched by honest emotion but most are afraid to share their story in public. For a yoga studio, it makes a lot of sense to share the challenges as well as the joy of different individuals practicing yoga. It might inspire someone who is reluctant or intimidated to visit a yoga studio to give it a try after reading about someone who also felt the same way.
Adding that human interest touch also reminds people of how much more alike we are than different and I think it helps people feel more comfortable and trusting when they read a refreshingly honest blog. Blogging can also help you educate or inform potential or current students and help you establish yourself as an expert in the field. So even though you might not actually be an expert, you can probably still share something they don't know yet or perhaps just a different perspective. Over time, with accurate information, your reputation as an expert will grow.
Adding that personal touch might not make sense if you are writing a blog on a technical explanation of something but I think for most blogs it makes sense and it makes it more interesting.