The vast majority can talk to the software. The training capabilities are still there, and will improve your accuracy, but most of us don't have to train Simply Speaking before using it. If Simply Speaking has trouble understanding your accent, just train it. In the past, doctors had to wait hours or days to see their dictated report. Lawyers use it to prepare contracts, dictate court notes and manage legal paperwork.
Professionals can use it to prepare any type of report.
Realtors can use it to document properties. Secretaries and transcribing services can use it to save time and money. Journalists can use it to write newspaper and magazine articles. Anyone who produces lots of text can use it to speed up turn-around and reduce report costs. Simply Speaking software is probably not the version a doctor or lawyer would use.