Some people preorder special meals for variety, or just to try them
Some people are vegan. So, when they book a long-haul flight with free meal service, they'll preorder special meals which are vegan. This is fine.
Some other people eat meat every day. But they want to try some vegan airline food, to see if it's any better than regular airline fare. So, when they book their flight, they too will request vegan meals. I wonder whether or not this inconveniences the staff.
Still other people fly often, and preorder special meals for variety.
Special meals may take more work to prepare
One user claims:
"Airlines provide special meals as an accommodation for special needs (religious, medical, etc.), not as an à la carte option. As such, they require you to request special meals directly. This requirement helps to indirectly limit special meals to those who truly need them. If an airline essentially lets passengers order à la carte online, this makes catering the flight more costly and difficult.
"Some airlines do let you save your special-meal needs in your frequent-flyer profile. Others let you choose a special meal while booking. But many airlines require you to phone a call center."
Another user claims:
This burdens the caterers. They must plan the meals in advance, in order to ensure on-time departures.
FlyerTalk user "dia1" chimes in:
"From my observations: It would seem that, if you don't need to inconvenience [caterers and staff] by ordering special meals, it would be best not to. It's a different matter if you really need to."
B.) If you don't have any dietary restrictions, is it indeed best to avoid ordering special meals when you book your flight?
Please also read my post on how to preorder and actually get a special airline meal.