Sensible to keep in mind yes, absolutely (and easy to forget when your obsessing over typology..) But you do know we're talking about enneagram instinctual stacks?
The instinct theories seem useful in understanding why you can feel extremely attracted to someone (who might not be good for you) so they can be useful to know about. For me, a combination of socionics and enneagram knowledge is useful (I agree with lots of the observations you make on this site but I don't have the ability to make those observations myself or the wisdom!).
Ennegram knowledge (not just the instincts but tritype as well) helps me fine tune my understanding of socionics..meaning I can make more helpful observations myself. And having a clearer idea of why someone acts the way they do can help you get away from them quicker if you need to but don't feel able to.
Also I'm not saying you're criticising enneagram, just continuing discussion..
As a rule, yes, judge by actions- I have learnt the hard way not to assume someone will start being 'nicer' if you give them the benefit of the doubt..some people need you to have a discussion/even an argument with them to realise that they have been doing something wrong or to at least get them to consider a different way of behaving (i have isfp in mind..no offense to other isfp) These problems can be to do with sociotype/ enneagram type but they can also just be to do with maturity/ 'baggage' as you call it.
For example, with the guy I last had problems with, reading about typology helped me to see how he ended up behaving the way he did...but it is probably due to his previous recent break up/ also being younger than me, and my own baggage that the situation was quite so challenging and ridiculous.....
I can also understand better why I was drawn to him and don't feel so silly about it now.
Sorry for going on bout my 'baggage' lol