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.
(..) sent to your next stop. Seriously? And your pack, it's insane. We need to do a little pruning. Okay, so I'm gonna pick out the stuff that's useless to you. And you can leave it in the free box unless you can give me a good reason why you need it with you. - Okay? - Okay. (..)2014 Wild