Disclaimer: From what I understand so far ... First, it seems spirits have different specialties. It may not be so easy to affect the material world without a physical avatar designed for the task, but it can be done and some put in the work to learn how. I think the advanced form of this skill led to the stories of angelic beings that manifest to converse or intervene, then vanish. Others can only "telepathically" link to aware embodied souls and direct events by creating hunches and such. Some might tip the odds of one thing happening over another, leading to synchronicity. So the answer to your questions is "it depends on his skill set." A "yes" is a definite possibility for both questions, and the history within mythology suggests that both have happened around the world. Second, how we connect to the physical is basically via energy. We perceive limited bandwidths of energy within our human forms, but like the rainbow they are all "one" including those we can't sense while embodied. Bodies aren't just material. They are constructed of energy that is only sensed as tangible within a certain band of resonance. From what I understand, the physical body is structured to receive the higher level energy of our souls and transpose that information down to the level of resonance with the tangible avatar. This process leads to a feeling of disconnect because of the the intense focus within the physical on a specific bandwidth, but it's not an actual disconnect. The full spectrum remains present at all times. Where there is a physical presence of any kind the higher levels of energy are always intertwined even when we can't sense them. Example: When you look through a microscope you may see a single cell. You might ask how that cell is affected or affects its organism, but to see that you'd have to zoom out a bit or look even closer. From the perspective of our spirits, our physical avatars perform a function along the lines of that microscope, only with many other sensors and interactive qualities giving us the chance to interact more easily on the physical bandwidth of energy. If you ask why? Well, why do people play multiplayer role playing games? Why are we so fascinated with the idea of virtual reality? Why do we want to build robots and then control them with our minds? I think the curiosity, invention, and imaginary worlds we are fascinated with as humans are a reflection of the attitude we have in spirit. Humanity seems to thrive on the enjoyment of exploring, experimenting, learning, challenging (self vs.whatever), creating, connecting, etc. It would not surprise me to find those same motives within our higher selves, just acting based on a larger scope of information. Finally--back to the original topic--I don't think there is just one reason for us to participate in this physical life. Why would there need to be just one? Whatever reason makes the most sense to an individual is the only reason they really need, even if that explanation for physical existence feels pointless or out of control. Those of us who see life through a more optimistic lens can't force that view on anyone even if we think it will improve their experience significantly. After all, we do get to choose the story we tell ourselves in order to cope with the vast number of influences we can't directly sense or explain.