> BEGIN? Take 60 seconds to read what it means.

Yes, that's exactly the problem: it's additional mental load you have to read up on.

Have 60 of those small oddities in a file, and suddenly you're spending an hour dealing with Perl quirks rather than actually debugging that obscure script a retired coworker wrote a decade ago. A 5-minute fix turned into a 65-minute fix, solely because of Perl.

Most programming languages use more-or-less the same constructs, and the few per-language oddities are usually fairly obvious from context. In practice this means someone familiar with any programming language will to a certain extent be able to read, debug, and patch small issues in code written in any other programming language. Perl's obscure and dense syntax makes this virtually impossible. Give a buggy Python script to a developer who daily-drives Javascript and they can probably fix it. Give a buggy Perl script to that same Javascript developer, and they probably have absolutely no clue what's going on.

In practice this turns Perl into technical debt. It has very few natural niches where it is genuinely the best, so experienced Perl developers are quite rare to have around. Any script written in Perl will most likely have to be read by someone who isn't an experienced Perl developer - which is significantly harder than a script written in just about any other language. The result is that any Perl scripts you have lying around are basically a grenade waiting to go off: they can't be maintained, so they should probably be replaced.