No they are not. The standard may be delayed but most compilers ship these features already.
They are shipped experimental and most people will not use them. Even those who use them will limit use as they have been burned before by something experimental changing when it was finally stable.
With all due respect, but C++ codebases are often at least two standards behind the current one. "Most people will not use them" is true even for C++20 (features) right now. The people that care about the bleeding edge of C++ use them right away after a compiler adds experimental support.