I haven't seen any discussion of this.
To me the biggest problem is what checked_add would even mean for floats. Arithmetic on floats starts to "fail" due to rounding errors long before they hit their absolute maximum value. For some values x + 1 == x. Should that fail? But that is the same problem as 0.1 + 0.2 != 0.3, just with an arbitrarily larger error bound.