To put things in their proper context and perspective, Richard Bartle published his paper in 1996, when some of the most popular MMOs were MUDs.
The test @erjoh linked to was designed over the course of a few weeks in December 1999 and January 2000, not by Bartle himself, but by Brandon Downey and Erwin Andreasen, who also thought of it as a MUD personality test.
So yeah, don’t take it super-seriously. At this point, it’s basically a step above MBTI. 