On the upside, as an hourly worker, you would get overtime if you need to work > 40 hours in a week, and typically get extra pay for work-related travel because it entails working outside regular hours.

As you likely know, salaried employees can be called upon to work more than 40-hour weeks for no pay increase, and don't get extra pay for flying (say) on Sunday night to a Monday-morning work-related meeting.

IIRC, increased scrutiny of this distinction came about because people who had "salaried" positions (at relatively low pay, with limited scope of responsibility) were being asked to put in extra hours, and there was a lawsuit.

At my organization, BS-level new grads will be on-boarded as Overtime Eligible (i.e., hourly). Within 1-2 years they will in almost all cases be promoted to the next career level, which is salaried (also known as "Exempt"). PhD-level new grads are on-boarded as salaried.