Framing terrace, driveway, splash guard without curbstones

Tomorrow,

we had another appointment with the landscape gardener... He suggested that the terrace (80x40x5 concrete slab), paths around the house (60x40x5 concrete slab), driveway (multi-format 8cm) and the splash protection could also be done without curbstones because it looks better... My wife naturally likes that very much.......
Is that possible? I think, for example, that for the terrace and paths the concrete wedge can only be made 2-3cm against the slab and in a few years everything will then slip away?!
It’s not about saving curbstones - if it makes sense, of course we will do it...

Is there a standard or something else for this? The landscape gardener probably doesn’t care what happens after the 2-year warranty...

Thanks

and also execute the splash guard without border stones because it looks better...

This is a waiver of the last 10 cm of flood protection. In heavy rain, the water will be right up against the house. I would only do that on a mountaintop. Quickly, there can be 10,000 liters of water on a property, from above or the nice neighbors.

I would only do that on a mountain peak.

Living on a slope... Can you do that safely near a path and terrace? Or will I regret it in 10 years?

Living on a slope... Can you do that without worries by the path and terrace?

If you are sure that water will never come down the hill. I would look closely during heavy rain where the water comes from and where it flows to, and then decide where edges go.

If you are sure that water never comes down the mountain. I would look carefully where the water comes from and where it flows during heavy rain and then decide where to put edges

The neighbor above has a wall on the border, so nothing comes down... However, the soil is clayey loam... When it rains, we currently have small ponds everywhere that then dry up again in 1-2 days

When it rains, we currently have small ponds everywhere that dry up again in 1-2 days

If it rains heavily, you have large ponds standing by the house.
For me, it would be clear to design edges and paths with a slope so that small and large ponds and streams drain, e.g., into a soakaway with overflow.