Sounds like "security by obscurity" to me - if you think AI is so good at finding security issues - it will find them in compiled code as well. Why not using it in your favor and let it search for bugs you'd otherwise not find?

You can lock down the source and also use AI to look for bugs in it. It does take significantly more time and money for AI to find bugs in compiled code.

That said, I agree with another commenter that this seems like more of a business decision than a security one.