Perimeter insulation 24mm advantage?

Hello,
My entire floor slab is above ground. Directly on it comes Poroton and a 20 cm floor structure.
Do I now have a significant advantage if I insulate the 24 cm perimeter of the floor slab?

You can now achieve an insulation standard that you would later only achieve at the expense of room height. -> Thicker insulation on raw floor.

Whether this ultimately pays off after xx years is a completely different question. If no subsidies are involved, it will probably not really pay off in most cases.

I mean on the outside of the 24cm high side of the base plate

You have to ask your planner the question. Basically, this area is probably the most sensitive area in the whole house. Because a thermal bridge tends to form in this area due to the concrete floor slab. Especially there in the base area, you quickly have condensation and thus mold.

We did this because it was the last component to raise our house to the KFW55 standard. This gave us the opportunity to take advantage of the promotional loan. The repayment grant amounts to €18,000, the additional costs for the perimeter insulation were €2,500, and there was another €3,500 for the energy consultant. We didn't need to calculate for long.

But it only makes sense if the house is already equipped in such a way that it just narrowly misses KFW55 anyway.

A KFW subsidy is no longer possible. I am only concerned with the meaningfulness.

I found this picture on the internet and marked the insulation here with the arrow which I am referring to. If I interpret the picture correctly here, it is relatively pointless?