Continuous muntins are practically frame components. Aluminum profiles have an outer and an inner shell with ribs in between for decoupling. Making them with muntins is a complex undertaking. For plastic, continuous muntins are a special design that also drives up the price significantly. For wood, the effort is somewhat less. Where muntins are deemed necessary for [Denkmalschutz], they are applied on the outside (however ordered separately, not DIY accessories).
In the installation depths of triple glazing, the muntins are naturally quite bulky, which can quickly give a reinforced glass feeling. Triple or double glazing differs by at least two centimeters in thickness, which also affects the sash and frame profiles to be chosen.
The thermal insulation gain of triple glazing does not come from one and a half times as much glass, but rather from twice as much air in between. Air insulates only where it is not replaced by something solid.
Forget muntins, forget continuous muntins even more thoroughly, rather enjoy the unobstructed view, the much faster cleaning, and the significantly lower price. And choose triple glazing—not because double glazing is too poor, but simply because it is the "upcoming substandard."
If the cost of muntins is not saved elsewhere in the window quality, a 1x1 m window runs into four digits. Around that amount, several annual vacations would be spent on muntins. For the dear wife, this can surely be converted into shoes and handbags as well
P.S.: Every multiple glazing requires a lot of force and makes a lot of noise when broken. The time for the burglar starts running from the moment they are noticed. Therefore, prying open is much more popular. But the protection against prying is the same, whether you use profiles for triple or double glazing.