I also use this little technique when slicing larger prints into pieces that will fit on the printer. My Maltese Falcon is an example of that; I wanted it to be the same size as the movie prop, which meant slicing it into three parts. Peg holes helped keep his parts flush at reassembly. (Clarification: I didn't create this awesome Falcon model; I printed someone else's model from Thingiverse.)
A couple of other interesting production notes. First, the to make the peg/hole arrangement really work well, the holes should be cylinders with different diameters at the ends. In this example my pegs have a diameter of 4.5mm. The holes have a diameter of 5mm at the opening and 4.6mm at the back, providing a snug pressure fit. The pieces actually stay together pretty well without any glue.
Second, note the orientation of the housing -- I printed it with the back side flat against the print bed, lens pointing up in the air. Why? The peg holes have a 90 degree overhangs. The one on the bottom could potentially sag during the print. Probably not a big worry in this case because the widest of those "roofs" is only 4.6mm, but it's still a good practice.
Sometime soon I'll post the OpenSCAD file for this model either here in my site or on Thingiverse.