Yes.
Because the alternative is idiotic, hard to read BS like fn.
The problem is that "fn" is optimizing the WRONG things: not only is your code going to be read more than it is ever written, but this abbreviated form is actively hostile towards domain-level subject-matter experts that you may want to audit or verify your code. Now, instead of him jumping into code that reads like English (Ada), now he has to 'decode' Rust BEFORE AND DURING his evaluation of the code, distracting him from his purpose.
The problem is that "fn" is optimizing the WRONG things: not only is your code going to be read more than it is ever written, but this abbreviated form is actively hostile towards domain-level subject-matter experts that you may want to audit or verify your code. Now, instead of him jumping into code that reads like English (Ada), now he has to 'decode' Rust BEFORE AND DURING his evaluation of the code, distracting him from his purpose.