The way they do it is fundamentally different. Head just reads until number of newlines is the target number. Tail has to first read the entire file and keep a buffer of the file and/or offsets for each line ending to determine what the last 10 (or so) lines are.

This idiot (Gabriel) probably thinks exclusively in the real world paper line analog.

I also just looked at each program's command line options and they're identical. Less things only Tail can do (because they're fundamentally different operations)