Even with a basement, you need a slab foundation - but not a strip foundation.
It depends on the ground.
We also built with a basement, since the property is on a slope. Half of the basement is completely free, resulting in 2 rooms + a bathroom with 40m². Also, for me, all the technology and heating system emotionally belong in the basement. And a larger storage room has to go there too. Here, the argument with the children is the most important one for me.
Whether we would build on flat ground without a basement, I don't know. If the plot is big enough, definitely. But here in our area, prices of around €400/m² are called for, and you don’t want to give too much of the outdoor areas to enclosed buildings. Also, the fees then increase again due to the larger sealed surface.
By the way, our basement cost us €67,000 excluding earthworks and interior finishing, a nice sum of money, but that also includes the basement of the garage, which adds another 34m² of storage space. So you can do without a garden shed.