OK, that may be a bit harsh. But the danger is that a translation that is out-of-date or badly done will turn you off the book. Many classic books whose translations are now beyond copyright are available for free. But these translations are, generally speaking, poor. To really appreciate these books, find a translation that is up-to-date and that suits your reading style.
https://en.wikipedia.org/wiki/Confessions_of_an_English_Opiu...
https://standardebooks.org/ebooks/thomas-de-quincey/confessi...
If you have some particular fondness for Victorian English, sure, read what you enjoy; but antiquated language doesn't make anything intrinsically better, and it takes the average modern reader further away from the work itself. These works weren't composed in a language that was, for their audience, hundreds of years out-of-date.
Moreover - particularly with ancient texts - older translators were typically writers first, scholars second. As pointed out elsewhere on this thread, Pope didn't even speak Greek when he "translated" the Iliad. The Butler translation here is prose. An approach to translation that takes fidelity seriously is a more modern invention.
I have found that modern translations inject a “modernness” into the language that isn’t present in translations from a century or two ago. If that doesn’t bother you, then sure, pick up a recent translation.