I understand Da’as Torah a bit differently and I think there are two related points when seeking Torah advice for non halachic issues:
1- the Torah can give a perspective on all areas of life, not just halacha and psak. Hafoch bah vehafoch bah dekula bah. However, that assumes that the Da’as Torah giving advice is also knowledgeable in that area. Da’as Torah is like a calculator- it will give you the right answer but only if you input the right information. If the Rav does not understand financial matters (for example), then his Torah perspective on the subject will be flawed because the “input” is incorrect.
2- I think there are two aspects of Avodas Hashem- objective and subjective. Objective is halacha- we have to follow halacha and we have to follow the psak of our Rabbonim. But so many aspects of our life are not directly and explicitly dictated by halacha- that doesn’t mean we are exempt from trying to do ratzon Hashem in those areas as well. But what ratzon Hashem is in those areas are affected by each person- his personality, situation in life, challenges, family, etc… Two people can be engaged in the same situation, and the Ratzon Hashem will be different. Getting a Torah perspective from Da’as Torah in these areas is crucial, but the Da’as Torah is still lacking the personal subjective side that only each individual person knows. Ultimately, even after getting a Torah perspective, the decision rests on the individual himself how to apply that to his situation and ensure he is doing Ratzon Hashem. No Rav can tell him that.
As an addendum to number 2- I think there is a great risk to relying on Da’as Torah blindly without factoring in our individuality. Oftentimes, when someone who doesn’t consult Rabbonim on serious, complex, and controversial issues… that person will make whatever decision he feels is best, but will usually feel some sort of guilt as there will be consequences to that decision. Nothing is ever black and white, and they will accept accountability for their decision. But I find that oftentimes, when someone blindly follows Daas Torah, they will view every situation as black and white, and they will ignore the repercussions of their decision. Even correct decisions come with consequences, and part of healthy growth is accepting responsibility and accountability for those decisions. I sometimes feel that relying on Daas Torah is a crutch for many people to dump the accountability to the Rav who is advising them, so they can mentally ignore any adverse consequences to their decision.