I did this, primarily because I'd done computational biology research and wanted to strengthen my quantitative skills.
In terms of its impact on my apps, I'd say it was neither here nor there. I occasionally talked about it in interviews, and it led nicely into talking about my comp bio research.
I'd argue though that there may be faster and less expensive ways to gain the skills you're looking for. Most coding bootcamps are only a few months, and they do a good job at providing you a strong foundation in coding.