A question about PCT versus CNA training

A friend of mine has decided to take PCT classes instead of the CNA course at a local tech school. Her reasoning is that while she realizes she probably will start out working as a CNA in an LTC facility anyway, the extra training will come in handy in the long run. That has me thinking...why don't more potential CNA's study to become PCT's instead...if only to make them more marketable when looking for a job?