This reads like a dogmatic view of someone who hasn’t worked on a project that’s a million plus lines of code where something is always going wrong, and crashing the entire program when that’s the case is simply unacceptable.
tldr: undefined constants were treated as a string (+ a warning), so `$x = FOO` was `$x = "FOO"` + a warning if `FOO` was not a defined constant. Thankfully this feature was removed in PHP 8.
If the error isn’t repairable by the user, blocking them from using the app entirely is mean. If the error screen has a message telling the user where to go to set their name, that’s fine but annoying. If the error screen tells the user they can’t use the app until someone checks a dashboard and sees a large enough increase in errors to investigate, that’s a bigger problem.
