Yes, that is a great realisation, i believe. I have seen this too, for what its worth.
The EBT texts distinguishes a noble path that is connected to merit but still not based or connected with purity (MN117). It is a Path of bright kamma leading to bright results in time such as relative health, long lifespan, wealth, beauty, higher rebirth. But an sich this is not a Path that frees from suffering and samsara. Because also those kamma vipaka’s, fruits, cease ofcourse.
Some believe this is only taught in MN117 and consider this sutta’s as fake, as late or something like that, but no, this distinction is everywhere and the base of Dhamma.
As you also know merit is also describes in EBT as a bond. An awakened mind is also beyond clinging to the bond of merit and demerit (dhp412). Merit leads, as it were, upwards in samsara, demerit downwards, but this is all mundane Path, not supra mundane.
There is also the Path, supra mundane, connected to purity, connected to the kamma that makes an end to bright kamma, dark kamma and mixed kamma. This is the stream. The above is not really the stream that leads to Nibbana.
That is also self-evident, because one has not entered the stream if one is born in a buddhist country and holds all these mundane right views, has good intention, speech, actions etc. There must also be some personal breaktrough in understanding. One cannot say that being on the noble mundane path one has entered the stream.
If the sutta’s talk about the noble path as the stream that leads to Nibbana that refers to the supra mundane path that one has found, meaning, i believe, one understand the difference between purity and impurity, mind with ego and mind without ego. One also understands now that no real quality is ones own. Not wisdom, not love, not compassion. Thinking that such qualities can be ones own, ones possession, is seen as delusional.
I also agree with you that Buddha does not reject the impure desires to want this or that for oneself.
And relate to the Dhamma as some investment into ones future. Alhtough impure the Buddha does not reject this. But is easy to know this is impure.
But, on the other hand, the texts are also very clear that reaching for higher rebirth or other wordly goals for oneself such as health, long life etc, is still being under the spell of Mara. I think that these goals do not really show understanding of Dhamma but Buddha apparantly also did not disapprove of it knowing how human nature is.
For me personally Dhamma is especially about recognising purity, the supra mundane path. I feel this is something that can be seen in any religion. All religions understand egocentric desires as not a Path to Truth and fulfillment and end of suffering. They all share this same truth.
The stream, the supra mundane is not buddhist at all. It is something beyond any religion, culture, raising and beyond merit and demerit. It is non-sectarian. Buddha only re-discovered it. Did not invent it.