Mostly because I understand mbti, enneagram, and variants. I really don't think you can type properly without all these factors. Variants and EType being just as important as mbti. For example; an estj 3 sp/sx and a estj 8w7 soc/sp will seem drastically different. Without understanding etype and stackings in addition to mbti, you'd probably mistype that ESTJ 3 sp/sx because they're less typical of the type. I'm quite unimpressed with the typing Ive seen particularly in this sub forum. I'm not saying everyone here is terrible at typing. There may be someone whos better at it than I am. But I havnt seen it yet. People aren't even getting the temperaments correct. Not too long ago I saw someone say Lindsey Lohan was ESFP but also couldve been an INFJ. WTF? Those types are completely opposite.
Really, if you need advice on typing I'm more than willing to help. I've studied mbti and the enneagram/stackings for about 7 years now. My professor in College (ENTP) regularly does seminars on mbti and Ive attended quite a few and exchanged ideas with him. It's something I know quite well. Ive read through "Please Understand Me" and various other mbti books. I assure you I'm not one of those ppl who only skimmed over a few profiles and thought I was an expert. Ive read through everything very thoroughly (ie. I know my shit).
Personally I dont think NFs are very good at typing from what Ive seen. Their conclusions seem completely random and without reason. Take that Lindsey Lohan example I gave above as proof. Heck, I even saw someone try typing Jessica Simpson as ENTP. Again, WTF!? INT's probably suffer from not having a good enough radar to gauge others. J-types also suffer in making accurate typings due to being, well, close minded and not taking everything into consideration. I've also seen numerous occasions where people openly admit they don't know a person well, but just go on a whim and throw out a random type. Some friendly advice, dont bother typing someone if you know absolutely nothing about them.
and maybe more importantly, I use it in real life. With Ne being dominant, I easily make connections between everything and anything. Everyone reminds me of someone else. with there being only 16 types, and meeting thousands of people, it's easy to connect people to one another. Hence, if person A is a definite Type ----, and person B strikes me as being very similar to them, I already have a good groundwork for typing person B. Most likely they have something in common, weather its mbti or enneagram or stacking.