Thank you for replying. I personally wasn't saying that I'd want any ability to force Binding(get: { ... }, set: { ... }) but rather the sweet spot of the current proposal, which in my mind would look like this:
Binding<...>
get: { ... }
set: { ... }
Binding is just one example of many. It doesn't have to be an init like this. The review thread showed other examples similar to this.
I respect the core team's decision, but I don't agree nor understand it.