Historically, block letters were taught to young children first because they were seen as less difficult to form, and therefore writing by someone with little fine motor control would be somewhat legible. Cursive was how adults wrote. In that sense, she was correct.
That said, "the writing of the business world" today is Times New Roman (or maybe Helvetica Neue). It replaced the Palmer Method of Business Writing[1], which is quite distinct from the the cursive that is taught in schools today (Zaner-Bloser[2] or D'Nealian[3]).
1: https://en.wikipedia.org/wiki/Palmer_Method
2: http://content.yudu.com/web/y5b2/0A3vbrb/16Grade6Student/htm...