What guests do with the four hours afterwards
The real argument for a daylight booking is not anything that happens during it, and guests usually discover that only once, by accident. It tends to happen while walking somewhere at four o'clock.
An evening booking is followed by sleep. That is not a complaint about evenings; it is a description of where they sit. Whatever happens at ten at night, the next thing on the schedule is bed, and quite often the sleep itself is poorer than it would have been, because a body takes a while to come down and one in the morning is a bad hour to be waiting for it.
An afternoon booking is followed by an afternoon. That single structural fact is what guests write back about, and they are usually slightly surprised by it.
What they actually do
Nothing exotic, which is exactly the point. A long walk, often the one that had been planned for three days and kept getting displaced. The museum with the queue that is shorter at four. A coffee somewhere with water in front of it. A slow hour along the canal ring in the Jordaan, or a circuit of Vondelpark that takes longer than intended because there is no reason to hurry.
Quite a few take a nap, and the nap is worth a sentence of its own because it is a different object from the sleep after an evening booking. It is chosen, it is forty minutes, and it is followed by an evening rather than by a morning with a flight in it.
The dinner that is now a good dinner
On a trip where dinner at eight was already fixed, the afternoon booking is the thing that makes the dinner easier rather than the thing that competes with it. You arrive at it unhurried, having had your own part of the day, without the low-level negotiation people conduct with themselves all evening about whether and when to slip away.
That is a subtler benefit than it sounds. A fair number of the evening bookings that go wrong go wrong because the guest spent the preceding four hours managing the logistics of getting to them, and arrived having already spent the energy the booking was for.
Flights
The clearest case of all. An evening flight and a daylight booking fit together without any tension at all: one o'clock until half past two, back in the room, out to Schiphol by four, and the day has had both things in it. The reverse arrangement does not exist. Nobody books at ten at night before a seven in the morning departure and enjoys either of them.
A room at Schiphol or an airport hotel is a separate arrangement in its own right, outside the forty to sixty minute window that covers central Amsterdam, and the journey time is agreed with you in writing before anything is fixed.
The one exception
Some guests want the day to end there, and for them the afternoon is simply the wrong shape. If what you are after is the thing that closes a day, then closing it at half past three and having four hours of light left is a mismatch, and no amount of arithmetic about corridors changes it. That is a preference and it is a perfectly good one.
For everybody else, the four hours are the part that is genuinely free. They were paid for by nothing, they cost nothing, and they belong entirely to the fact that the booking happened when the city was still awake and so were you.
A note on eating
The one thing guests regularly get wrong about the afternoon afterwards is food. A booking that finishes at half past three lands squarely in the gap where Amsterdam kitchens are closed, between the end of lunch and the start of dinner service, and a guest who skipped lunch because of the booking then spends an hour looking for somewhere.
Eat before, lightly, and the problem does not arise. A small lunch at half past twelve is the right shape for a two o'clock booking in any case, since a long one with wine is the reason an afternoon occasionally feels like an evening. If you would rather eat afterwards, the practical answer in most of the centre is coffee and something small at four, then a proper dinner at seven, which is what the city itself does.