Your quote is incomplete: "it replaces our die and warn
sighandlers". The point of the code is to be drop-in and not require any other changes in your code. In fact, it would be better to call it in an eval so if it's not installed, it doesn't break anything:
BEGIN { eval 'use warnings::colored' };.
Changing die to dye would require you to change any code that uses it, and also it wouldn't then work on anything that internally called die or warn, like the example: system 'nonexistent-command'.
If the %SIG entries could be tied variables, then it might be possible to make this play nice with Carp::Always. I haven't looked into that because it works fine enough as it is for me. That's why I released it anonymously and not to CPAN. If somebody wants to improve on it and deal with the edge cases, feel free to release it.