Both if you wanna share. I’ll screenshot so I don’t convince myself a big cheese block is okay.
In soil, root mass is critical so the plant can stay hydrated, fed, and breathe. It has to seek out the big 3, which is how you cheat in soil.
In hydro, air, water, and nutrients are all easily available. With a natural root mass, the plant will grow longer, skinnier, less fibrous roots. Those small fibers can uptake easier, as they have more surface area than one long root. Think of your foliage if you never did training... Christmas tree.
Now, when you prune them, they will shit fibers all over, just like if you topped your plant. In return, those fibers will uptake the big 3 quicker. The fibers are also much smaller and have less wall to penetrate, as opposed to a thicker root that must penetrate further. If you have microbes, more fibers also means more area to colonize.
Lastly, since you now know all that, less root mass means more water in the bucket, which means more stable ph/ppm. Ph swings kill microbes.