On the contrary, I think this is a very intelligent question!
I agree with Paulo that the possibility to fit a bimini is probably the most important reason why so many production boats have only a short traveler on the coach roof. Charterers want bimini’s and charter companies are very important clients for mass production boatyards.
Having the downhaul at hand to release it in case of emergency is a good thing. But to be able to master and trim a big mainsail, especially upwind, a performant traveler is essential. Unless you have a very powerful downhaul to control the leach and twist of the sail efficiently, which production boats almost never provide. In addition, the increasingly popular German sheeting system is not practical to respond quickly to puffs and lulls by means of the main sheet.
A traveler on the coachroof is completely out of hand, impossible to manage without using the winches and therefore almost never used. So I wonder why most builders even bother to fit it…
A big bimini is not only important to the "charters" but to any cruiser on a hot climate were most people sails. If you do not have a big bimini you have to mount some kind of shade (a tent on the boom) when you are at anchor.
That is a lot less practical and besides you cannot use it when sailing and the small bimini that a traveler aft permits is not always sufficient to provide shade when you sail. A traveler aft also obstructs the cockpit and make it less agreeable to "passengers".
I will trade the nice things a good big bimini provides and a less clean cockpit by a traveler near the wheel but that is a personal choice and one that is pretty marginal. Most cruisers will chose the big bimini and that's why practically all cruising boats have the traveler over the cabin. Only the cruiser racers have the traveler on the back of the boat because only the ones that chose that kind of boat prefer that option.
The Jeanneau 409 is a cruiser, a fast cruiser, but with no pretensions to be a cruiser racer and so almost all the ones that would chose that boat would prefer the traveler over the cabin.
And Erick you are right, most of the cruisers don't really use the traveler and that's why most of the big production cruisers don't have a traveler anymore:
The Hanses, the Bavarias, the Benetau and even the new Jeanneau 379 don't have one. I believe that the Jeanneau 409 still has one (and not a small one) because it is more sportive than the other mentioned cruisers and the sailors that will buy it will probably use it and want one.
Regarding what you say about the traveler I agree with you, it is not practical to respond quickly to puffs and lulls, unless you have a crew member on it, but otherwise you can perfectly shape the main correctly with it ( I used one on the Bavaria 36). With another crew member on it, providing it is a strong one you don't need to use the winches to control the traveler. Many times on strong winds me and my kid played with the boat, kind of doing 8K with 25/30K wind with a 2th reef at 90º. The boat on the limit reacted as a big dingy and it was indispensable a lot of work with the traveler and the wheel.
Contrary to the cruisers that have the main boom control on the cockpit (most of them), with the German sheeting you can really respond quickly to any emergency letting the boom go even if you sail solo.
Not as good and practical as having the main boom control and the traveller at hand but certainly a lot better than having both controls over the cockpit as it is usual in all cruisers without German sheeting.
I think that you would agree that a good traveler over the cockpit is a lot better than no traveler at all and that is what the Jeanneau 409 has and the vast majority of other cruisers don't have, a traveler and the main boom control line at the wheel