I would claim that you can’t think about transness without the typology. Not really, at least; you can do vague analogies and generalizations, but you will quickly get stuck in any real question.
Consider some basic questions that people may ask. The first one is “Am I trans or is it just a fetish?”, which the typology has an easy answer to, whereas there is absolutely no consensus on how to answer it without. Do non-trans AGPs exist? Do some of them want to be women? If so, how can you tell the difference? Does it matter? There are no answers to this without the typology. Some people will claim to have the answer, but they generally don’t have any underlying theory to back up their answer.
In fact, for most trans people, the typology provides huge shortcuts for questioning. Are you considering whether you are trans for some odd, non-trans-related reason, such as low self-esteem, anxiety, or internalized sexism? No, it’s obviously the A*P. Without the typology, it’s hard to see how you can provide a proper, theory-based answer to this. How about this one: are you fake trans because you showed no signs as a kid? No, it’s the HSTSs who usually show such signs.
I do surveys, and in those surveys a lot of people report that they want to be the opposite sex. How do I interpret these answers? How can I know whether they are “trans-spectrum”, in the sense of having related traits to actually transitioning people, or just being weird outliers? Heck, how can we know this with other groups, such as nonbinary, genderqueer or genderfluid people, who seem to be similar in some but not all aspects to trans people? The typology provides the answer: look into whether they are gay or A*P, and if they are, they’re on the trans spectrum.
How’s the progress on making trans people transition earlier? Well, we’ve got a bunch of youngsters on puberty blockers. Will this eventually be the situation for the majority of trans people? How do we make it the situation? Turns out, there’s two kinds, and we’re only really catching one; this is a clear spot that needs innovation, and the typology helps identifying the relevant patients.
What about people who know they’re trans-spectrum, but need to know whether to transition. How does the typology help them? Well, it gives them clear definitions of the intensities of their situations, and tells them which trans people to compare themselves to. It also helps research into the outcomes of non-transitioners, as it tells you who exactly these are. This is useful for evaluating the alternative options to transition.
There are a lot of questions that the typology still leaves open, but it also provides a basic framework for researching them. Under what circumstances should you transition? What’s up with the transkid “desisters”? How about the new big wave of AFAB transitioners?
I used to believe in magical innate gender identity and brainsex and bodymaps and all of these ad-hoc ideas, but they are just not comparable in terms of raw usefulness to the basics of the typology.