Let's say that I have $2k to spend on headphones. Let's say I feel like I could also give some of that to the local food bank or to a local museum or another group that needs a donation. Let's also assume that I love my luxury sound so much that I would spend the $2k on headphones if I could hear a difference.
Ok, so now I test out two pairs of headphones. Let's say they are $1000 different in price -- $2000 and $1000. If I honestly cannot hear a difference, I get great headphones and create a huge benefit for people who really need some help. If I don't try to hear a difference, I'm not being honest with myself when I think, I really want to help people who need it.
*That's* the reason debunking the placebo effect might matter for me.