AviraDeArah> Torah lishma is your intention, not your methodology.
this is an interesting question.. We discussed here recently a Maharal in Netivos Olam that explains why a confused Bavli won popularity context against a more knowledgeable Yerushalmi .. [just imagine all Tannaim who made fun of those in the West seeing yeshivot learning Bavli, they’ll be confused more than Moshe in R’ Akiva’s class]. So, Maharal sees that Bavli had to reconstruct missing information and developed a method to do that (akin to modern pattern analysis – my words, not Maharal’s). So, now we can apply the same method to new situations. Thus, Bavli turned out more useful for future generations than Yerushalmi.
So, if I understand you correctly that we need to only learn halakhic conclusions without thinking how the authors came up to that, Maharal above seem to support the idea that learning how to think is also Torah. And there is enough in the Torah that different people can enjoy different parts of it. We don’t need to argue which part is more important.
Even in pure halakhic analysis, you may want to know the approach. for example, if you have multiple opinion, but many of them come from the same school or are independent opinions; whether they are using rational argument or relying on mesorah, and how strong that mesorah is; and whether underlying assumptions of the rational argument hold in current times.