Sure, you can use Python 3 if you want. If you are the only one using the scripts, you control the environment, and you know everything will always be UTF8, then no worries. It's roughly equivalent to setting PERL_UNICODE=SDAL in your environment (see perldoc perlrun).

Be sure to read the '𝔸 𝕤 𝕤 𝕦 𝕞 𝕖 𝔹 𝕣 𝕠 𝕜 𝕖 𝕟 𝕟 𝕖 𝕤 𝕤" section of Tom Christiansen's post from that I linked above, as nearly his entire post applies to any programming language.

If the "brokeness" of Python is because it cannot handle non-UTF8 properly, that would not impact me at all, as everything I'm doing is with UTF8.

I didn't say that Python 3 does not handle non-UTF8 properly, I only said that it considers (almost) everything UTF8 by default, which is not the same at all. You can certainly read/write files in almost any encoding you want, but you have to take an extra step to do so.

Edit: I forgot to include a link to perldoc perlunicook (and the original on perl.com), which is more of Tom's writing on Perl and Unicode