But you're moving to a safer subset, not a safer superset, so it still shouldn't require significant alterations.
The problem here is compiler support and performance.
And of course, but those will come in time. The point of it is that C++ isn't any safer (And actually, I would say is more risky in some aspects, because of the differences between (For example) the UB in C and C++), while Checked C is guaranteed to be safer, to a certain degree.