It's not really an issue if the string you're matching might have those characters. It's an issue if the regex you are matching that string might need to match those characters verbatim. Which is actually pretty common with ()[]$ when you're matching phone numbers, prices etc - so you end up having to escape a lot, and regex is less readable especially if it also has to use those same characters as regex operators. On the other hand, it would be very uncommon to want to literally match, say, ⦑⦒ or ⟦⟧.