I think I understand what you mean, I had a similar point of view, and I agree with you. However that in itself isnt enough to be consider as it Matters, to us human beings such acts of caring, striving and finding purpose means something, but the universe is constant in its view, what is inside us matters only to Us, humans, the universe doesnt care how we feel. Let me try to get some of my point accross:
You said what is reality and illusion? to answer that, we'll have to go back to the hardest possible question in the world, How did everything came to be, from nothing? religion says god, but science needs its own logic. So how did everything came to be from nothingness? that question had been haunting me most of my life until I finally came up with a Solid, and Quite sensible answer. But by the time I had and I discussed it with my physics teacher, he told me that the latest theory regarding that question is quite similar to mine. i was quite bummd naturally since I felt it was original, but none the less it kinda added to my theory, almost confirming it if anything. I will not share it here, as most claim it their own, however to make it short Nothingness and Existence are two sides of the same coin, they are not seperate, everything is nothing, nothing is everything, I know this may have you confused, but trust me if I give you the full theory you'd agree with me. The point is Reality and Illusion are basically one and the same, what makes reality matter? Only us! without us, reality as I said is merely in a constant changing process, as it was born, so may it dissappear someday, does it care? does it matter? No. We on the otherhand are quite the amazing creations, inside our heads is like a Universe in its own, a mini universe, yet a universe where things matter, where we matter, does it mean we do? the answer is Yes and No, like everything else I told you, the reality we believe matters to us, although essentially its an illusion. In the long run, and Scientifically speaking, the only thing that might truly make a difference, or matter any, is if the fundamental law of everything and nothing, reality and illusion changes, and as far as I can think, the only thing capable of even coming close to matterness, is Eternity. If the universe and Us humans were to exist and live for all Eternity, never fading, then we would basically remove the other side of this, (nothingness, and nonexistence) would no longer be a concept, there would only be something, everything, what we are and what everything is would define us indefinitely, the concept of definition would change, and we would replace our "potential" with a solid and unchangeable truth, we exist, we matter. Because reality and illusion would no longer be mixed, completely seperate, thus what exists within the realm of existence, matters, even if to the point of 0..0001, its still something.
I hope you understood at least a little of what m trying to say, cuz its always been hard to explain this part to folks who value emotions and humanity above all