100% Perlite as an inert medium should work to grow plants. Perlite, rockwool, roots in bubbling water, whatever - It's all hydroponics with the water/feed and root access to air pretty what matters.
But I would worry that 100% perlite just has no form, is so lightweight, it can shift around too easily, that even minor movement of the plant could cause below ground movement and damage root hairs attached to the perlite. While with even say 50% coco, you have a lot more dense particles that hold together better, with plant movement not affecting the roots below. For example, a decent size plant in coco/perlite if tipped over is only going to spill out some medium, But with 100% coco, it seems the plant could move around in the pot, tearing roots; maybe even slip/spill out of the pot. With perlite, there is much less to anchor-down the plant.
