Why are medical technicians trying to get nursing assistant certifications??

Since I graduated from a health sciences college, I have many acquaintances working in hospital administration teams or as medical technicians, such as
dental hygienists, optometrists, ophthalmic technicians, clinical pathologists, and radiographers.
A common denominator among them is that they either already have a nursing assistant certification, are attending an academy, or have plans to obtain one in the future.
In particular, most women seem very interested in getting a nursing assistant certification.
Does anyone know why? Is it to work two jobs??