It goes on in layers, not coats
Emulsion paint is two coats of the same product. A decorative finish is a series of different layers with different jobs — a base that seals and gives the background colour, one or more of a material loaded with filler, and a final layer that seals or polishes — and each one has to be dry and at just the right point before the next goes on. Skipping a waiting time does not show on day one: it shows three months later.
