Drainage channel / facade gutter for floor-to-ceiling windows

Hello,

I have obtained some quotes from landscape gardeners and keep coming across the item:

Aco Profiline X facade gutter channel element PP GF, BL 1000 mm width 155 mm, construction height 50 mm.
Galvanized mesh grate
MW 30/10, BL 1000 mm
Pure material costs for 22 linear meters are about €3000.

We have about 12 linear meters of floor-to-ceiling fixed glazed windows and 10 linear meters of floor-to-ceiling windows/sliding doors. Do I really have to install a gutter channel even with fixed glazing instead of laying the terrace directly on drain mortar? Nothing should happen with closed glazing. I understand it with doors... it would save a lot of money.
Or are gutters anyway unnecessary due to a slope and a roof overhang of 70 cm?

In wind and snowfall, snow is pressed up to 30 cm high against the windows. Despite the terrace roof with 4 meters depth. Depends on the wind. Your roof overhang is therefore useless. However, living in a region with regular snowfall. I can't contribute anything regarding the fixed glazing.

What do you have in front of the window? If you have a gravel strip there, I would forgo gutters. The water seeps away that way as well. If the terrace is directly in front (possibly also with a slight height difference), a gutter is recommended. We will still do without it in our case because the terrace is covered and lies above the original ground level. But I do not have to guarantee my own work.

Yes, there is a terrace directly in front of it. Then I will install a channel at all doors. For the fixed glazing where no opening is possible, I will omit them. Does he have recommendations for good/inexpensive channels? The Aco ones seem quite expensive to me.