Looks absolutely matter, but I think it's a bit deeper than the surface level shit people associate with attractiveness (usually ugly people who think it's "vain" to care about how you look or how your mate looks, which is just an excuse for their own laziness and mediocrity).
Looking good requires effort:
You have to be physically fit, which requires working out regularly and eating a healthy diet.
It requires you to get adequate sunlight so your skin looks more vibrant.
You have to actually put some thought into the clothes you wear and how they fit your body (and when you work out, everything fits and looks better on you).
You have to practice good hygiene and have an actual hair style.
All of these things not only make you look better externally, but also most of them make you healthier internally as well. And from an evolutionary standpoint, attractiveness = healthier, which = better reproductive fitness, which = higher quality and better looking mates.
Looking good also increases your confidence exponentially, and confidence is extremely attractive to the opposite sex as well as being good for your own mindset.
Furthermore, because of the effort involved, it shows you're not a lazy slob and that you're willing to put the required work into achieving something that many others aren't willing to do. It sets you apart from mediocrity.
Everyone dates somewhere close to their own integer. If you're a 5, you aren't going to get a 9-10. I'm sure someone is going to say "but if you're rich it doesn't matter." Yes it still fucking does, at least if you want your partner to actually be attracted to you. Very few highly attractive women will actually be able to get aroused and fuck some abhorrent slob who's obese and has no personal hygiene, even if he is wealthy.
And yes, society absolutely treats attractive people differently than they treat unattractive people.
You don't have to be born with it either, nor do you have to slather makeup all over your face if you're a female. Everyone can start exercising, choose healthy food options, groom themselves regularly and practice good hygiene, and do the little things that make a major difference in how you look and feel.
