I fund my cats with my disability money as they are indeed helpful for my mental health problems, I get this benefit whether I work or not, it goes on things that improve my well being and allow me more independence, like paying for a cleaner or carer, hiring a mobility scooter, paying for taxis and delivery charges for food shopping, buying aids for making certain things easier, like my shower seat, front fastening bras, decent shoes that won't worsen my gait. etc.
Sometimes it's spent on things that simply make me feel better, because it's fairly easy to become depressed when you suffer with chronic pain. With my cats, I had a reason to get out of bed, they made me laugh a lot, and stroking animals raises oxytocin, which combats anxiety/depression. It's why therapy animals are used.
People use the word benefits as a collective term when actually I think it's different depending on your situation. It would most likely be irresponsible to go and buy a puppy when on Jobseekers, but not as a pensioner or a disabled person. When you want people to "feel poor" on benefits, I wonder how terrible my life would be if that were the case for disabled folks like me. I'm not even sure I'd be here if I was in such an awful position and stuck there, when you are at your worst, and everything hurts, and doing something as basic as brushing your hair seems impossible, you do find yourself considering whether it might be better not to be here.