There's still the need for logging and assertion functions, where you want to test the debugging level or some other value before you evaluate the arguments to the function. Right now, you need to use a macro, but there's a proposal:

James Dennett and Geoff Romer. P0927R2: Towards A (Lazy) Forwarding Mechanism for C++. ISO/IEC C++ Standards Committee Paper. 2018. url: https://wg21.link/p0927r2.