Interesting. I did the full-length, formal Myers-Briggs analysis in grad school, and ended up as a nominal ISTP. Other than introversion, my results went really close down the middle, so depending on the day I can end up as something else, like INTJ or INFJ. I do think I interact with the world from a pretty ISTP standpoint, though--it tends to fit me better than any of the other variants, even though I'm not particularly technical and do not enjoy fiddling with bits of machinery.
The quiz had me as an ENFJ. I've never gotten E before, and am definitely not an E. I think their questions were slanted pretty heavily towards the "are you shy" and "do you have trouble talking to people" side of the equation, which is not where my introversion shows up--I love people and am very social, just need alone time as well to recharge. Their description of an ENFJ does not sound like me AT ALL. But I don't really vibe with this website's description of ISTP either? IDK.
I think personality typing can be helpful as a tool for understanding interpersonal differences, but people can take it way too far and get overly invested in these fundamentally arbitrary categories.