Helpful vs. Useful
They are. I don't know if they're even used consistently in the interface. However, what they actually mean with "Helpful" is probably "Non disruptive" (e.g. not "asdasdadasdadsasadasds"), while "Useful" is a feedback that is also actionable, that helps improving the page (e.g. not "the article would be improved by a photo of Caesar": true, but impossible).
Actually it's possible that one of the two is a newer version of the other, but I don't know the exact differences. It seems that the two exist at the same time with a lot of confusion.[1] No idea how to mitigate this by translation...
I'll wait until something is done. Meanwhile, I'll leave "useful" messages untranslated.
There's less a difference in meaning, than there is in "results": both are used to evaluate how interesting the submitted feedback is.
Readers (anonymous, unconfirmed users) can only mark posts as helpful/unhelpful (and mark as abusive) Registered, confirmed users do not have these helpful/unhelpful tools, but a more detailed "useful/resolved/non-actionable/inappropriate" (and hide/request oversight/oversight)
All actions performed by registered users will be reflected in the different filters (view all "useful/resolved/...' posts) and will result in the feedback no longer being displayed in the "unmoderated" queue. Actions performed by readers will not have such effect: that feedback will still show up in the "unreviewed" queue. It will only help surface useful feedback in a "featured" filter.
Basically, helpful (for readers) and useful (for registered users) are pretty much the same in meaning, but for a different user group and with different effects.
Finally, to avoid the confusion I have translated "useful" as "constructive", as it preserves almost all the meaning in Galician.
One of these two is a voting, the other is a moderation flag. Please change the voting stuff to "Mostly helpful" and "Mostly not helpful" to indicate this.
Don't use "constructive". I don't think this is a good idea. A feedback does not need to be constructive to be helpful.
So provide some alternative translations, or change these messages.
My suggested translations are "Mostly helpful" and "Mostly not helpful". I can't change these messages. I was told multiple times now that it is not allowed to change the English messages. Who can do this then? I thought you can?
I don't find that translation so easy. This is the point: Galician word for "useful" and "helpful" is the same. Adding "Mostly" at the before "helpful" doesn't resolve my problem. I need a synonym to complete these translations. Or at least a different wording.