Things like Open Ticket used as a verb to create a bug report, or open a bug report, or as an adjective to indicate a bug report is still active. Or similar when ticket means a transportation or entertainment event. If your key is the English text, you can't translate those three usages differently which is not good.

But also, minor edits to the English text are hard to manage for the translations, some systems have a way to suggest an existing translation, but it requires a translator to affirmatively select it. If the key doesn't change, you can still use the existing translations until the translators review the English change and decide if they want to also make a similar change or not.

Of course, the worst thing that people try to do is numbers; there are tools for that, but trying to do Open Ticket vs Open Tickets as singular vs plural falls over with languages that have a form for one, two, three, or more, or even more forms.

And then you get people trying to do string math. Delete this ticket vs Delete this image need to be translated as whole units, you can't add 'delete this' to the type name, gendered verbs and objects and sometimes even more complex stuff makes it not work.