What is hydro drip exactly? Just a thinner paint dip?
It's thin but it's an entirely different painting technique that allows these warped patterns and all-over textures. The pattern is laid flat on top of water (or solution, no clue if it is actually pure water), then it wraps around whatever you plunge through it.
AFAIK, normal boards we call dipped are usually not physically dipped in paint, it's usually just how they call boards with paint that covers the whole thing, bottom, sides, top, most of the time they're hanged and spray painted.
Hydro dipping process exemple: