It's 'useless' trying to change her mind. = It's 'useless' to try to change her mind.
Drugs are 'useless' in treating the condition.
I made a 'useless' attempt at fixing the leak.
(..) - An herbal soak token. - Right. Hey, Rin, what's a foreman? Hmm. Something's coming. I wonder what. What useless scum is slinking around in the rain? I can't waste a token on you. Relax. Good morning. Enjoy. Have a nice bath. - For the radish spirit. (..)2001 Spirited Away
(..) I was wondering if you could give me a job. I don't want to hear such a stupid request. You're just a stinking, useless weakling. And this is certainly no place for humans. It's a bathhouse for the spirits. It's where they come to replenish themselves. (..)2001 Spirited Away