I am pretty shure Hasselblad doesn't have too much interest in allowing the X1d to be used like a digital back, otherwise they would have stated it and they would cannibalise their back sales
Hasselblad makes 1 digital back - the CFV-50c, the others are 'camera systems'. Most dedicated view/technical camera users are buying a Phase/Leaf back, though there are some outliers, mostly due to the screens in the IQ series, plus wireless tethering, and power (for someone trying to reuse a H back). The CFV-50c needs to be refreshed with the new screen, and wifi added. Selling both at the $9k price point would be fine, where folks can select which style of shooting and which camera form factor they want.
Using the X1D as a 'back' for someone wanting to shoot with a shuttered lens should be functional in so much as it'll sync, but that's it. It could even be a $1k USB-C adapter and then it's an option. Yes, it's pandering to the 5% of buyers who even care, but for those who'll put it in a bag with a -100c or a H5x+IQ280 and a set of lenses it's important.
I'm not worried about a focal plane shutter - Hasselblad hasn't done one in decades, why start now.