The earnest prayer of a righteous person has great power and produces wonderful results.
Exactly how to translate this verse is up for grabs. I like the point that the NLT rendering, along with other translations (see link, and other translations on Bible Gateway) makes. Real prayer is focused, whereas simply praying a prayer is not necessarily so, akin to when Isaiah (quoted by the Lord) says that people can praise God with their lips, while their hearts are far from him.
Whatever the correct way to translate this passage (and that seems up for grabs, or interpretation, but might be a good further study), I think the idea of earnestness or fervency, wholeheartedness in praying, is certainly apt and commendable. We are so good at doing religious things half heartedly, going through the motions. But faith, especially in difficult matters, but really in anything in this life wants to take hold of God, like Jacob of old, who wrestled with the angel of God (Genesis 32).
It’s not like in all of our weakness, we shouldn’t feebly utter a prayer. We should; we should pray all kinds of prayers. I think in part so that we make sure we’re not merely going through the motions, it is good to give at least some of our prayers the strong expression they deserve, sort of like making our words bold in print. It seems like in our human weakness, this helps me to be focused, and cut through my own denseness, or ineptitude, and through the spiritual resistance of the devil, and hopefully pray in the Spirit.
Prayer requires effort, and is part of the fight of faith we are in for the good of others, was well as for our own good in this life. In and through Jesus.