Slip resistance is the whole specification
A pool deck is the one decorative surface that is routinely walked on wet and barefoot, which rules out several finishes that look excellent everywhere else. Polished concrete is not a pool deck. A smooth trowelled and sealed slab is not a pool deck. What works is a texture with open profile — a light broom, a knockdown or texture-skin overlay, exposed aggregate, or a stamp with genuine relief rather than a shallow print. If a sealer is used it must be one with grit suspended in it, and that grit is not optional.