Competing against others to come out at the top _is_ useful labor. The best one wins usually and as a consumer you want the best products to come on top.
That’s not the case at all. Competition is integral to the system working. We have many laws to protect the market so that competition is viable like anti trust etc.
Competition is why you have good products. Can you explain to me what incentivizes Apple to make functional and impressive iPhones instead of selling us barely working phones without cameras?
2nd: If I think capitalists are parasites, why would I attribute any good that Apple makes to them? Clearly it is the people doing real work who is to praise for that.