Play is the work, not the reward for finishing the work
The habit of treating play as what happens once the learning is done gets the sequence exactly backwards.
The language gives it away. We say the children are just playing, or that they can play once they have finished. Both phrases position play as the residual category, the thing that fills the space between the parts of the day that count. Anyone who has watched a child spend forty minutes moving water between containers of different shapes knows that the description is false. That child is testing conservation, gravity, flow rate, the limits of their own hand control and the social question of whether the child beside them can be trusted with the good jug. There is no adult led activity in the room that would generate that density of thinking in that span of time.
The difficulty is that play does not announce itself. A worksheet produces a visible artefact, and visible artefacts are easy to show. Play produces understanding, which is invisible until it turns up later in some entirely different context. This asymmetry is why play keeps losing arguments it should win. The educator who can articulate what is happening in the water trough, in the language of thinking rather than the language of activities, is the one who can defend it. That articulation is a skill and it improves with practice. It is worth rehearsing out loud with colleagues until it is fluent, because the moment you need it is rarely the moment you are ready.
None of this makes play automatic or self sufficient. Play left entirely alone tends to run in grooves: the same three children in the same corner doing the same thing they did yesterday, competent and unchallenged. The professional contribution is knowing when a groove is deepening into mastery and when it has simply become a habit, and having something ready that opens it back up. That judgement is the job. It is not less demanding than teaching from a plan. It is more demanding, because the plan cannot be written in advance and must instead be assembled in real time from what you know about these particular children.