There are solutions to pass directly a 3 D object to a 3D printer. Somewhere in this process there is a slicer working with default settings. If the output is ok than there is nothing to criticize.

Slicers slice the 3D model into 2D slices of a certain thickness.

A slicer converts 3D format as stl into machine, material and model specific G code.

Slicers are very complex programs with lots of features and options. Slicers must understand the material characteristics, the printer and the 3 D model. It is therefore highly recommended to open manually a slicer program and observe how and what will be printed.