Fruitful
I heard a turn of phrase the other day that I like:
"Is this fruitful?"
As opposed to helpful. In particular, as opposed to useful.
I tend to be more interested in whether something is helpful more than whether it's true. I sometimes slip into saying "useful." That ends up feeling uncomfortable, and I realise I meant helpful. Useful means it's more like a tool. But helpful means it's more like a strategy.
Fruitful feels like it hits a sweet spot here. Practice is helpful, but it's not useful (in the sense that it's not a tool). Practice can't be reduced to it usefulness, but... it does get results. Regular, sustained, practice is definitely fruitful.
Added 2024-01-14.