With the same sensor tech and the same pixel pitch, per-pixel performance is essentially the same: similar noise, dynamic range, and ISO behavior. So the larger 100MP sensor’s main image-quality advantage is not that each pixel is better, but that it captures more total pixels over a larger area.

That gives you a few practical benefits:

• more resolution for large prints
• more cropping flexibility
• slightly cleaner results when downsized, because averaging more pixels can reduce visible noise
• potentially smoother tonal/color transitions if the camera records higher bit depth (one answer notes 16-bit color for the X2D)

If you do not need extra resolution, the benefit may be small in normal use. For many outputs, 60MP is already more than enough. In that case, the tradeoffs can matter more: smaller files, faster readout/shooting, and generally smaller/lighter/less expensive lenses on full frame.

So yes: for non-professional or non-specialist use, a 100MP medium-format camera may offer little practical benefit over a 60MP full-frame camera with similar sensor technology, unless you specifically want large prints, aggressive cropping, or maximum image data.