Getting to know each other

In the world of today, everything is changing faster and faster. Technical and social changes are happening at much faster pace. Yet there seem to be some things that haven't changed in decades or even centuries. Dating seems to be among them.
Sure, there's speed dating and stuff like that, but it seems that people still spend a lot of time to "get to know each other". It seems to be an unwritten law of the dating world that you've to spend a certain amount of weeks or months before you can talk frankly about certain emotions or desires you both might have. I wonder, why is that?
Isn't all this tip-toeing around against our nature?

Basically, we are visual beings. We see something and that information is transmitted to our brain where we get a short info like "there's a car heading our way, let's not cross the street" or "I'm hungry and there's food on the table, let's eat it".
Never once does our mind tell us "There's something that our body wants/needs, let's waste a huge amount of time just staring at it and pretending we don't want it before we take it"(risking that someone else will take it). With that kind of attitude, our species would be long gone by now.

So why do we behave so differently when it comes to dating? True, we should know another person before we get to intimate. Or do we? Do animals spend a lot of time courting? They usually just go right at it, right? And seeing how some humans behave, it seems to be just the same with them.

I just don't really want to understand what all this stalling should be good for. Basically, I walk around and I see other human beings. If my eyes see something I might like, they'll inform my brain. Thus, I'll be starring at that "object". That's natural, isn't it? So if now I'd walk over to that girl and just talk to her and say "hey, I like you, do you like me to and want to spend time together/be together", wouldn't that be the honest and natural thing to do?

What will I exactly win if I go there and pretend to be not too interested in her or by telling her "let's be friends first"? Like I said above, we're visual creatures. No one can tell me that our interest in another human being(at least upon our first encounter) is based on anything else but visual impressions and some assumptions thereafter(at best).
Or in a nutshell: If we see something we like, we want it. If that objects feels the same way about us, perfect, it's a match! So what would be the point in wasting valuable time, looking for someone else or pretending that it isn't so?

People say that it takes time to get to know another person. Be that as it may, but how much time do we actually need to really know another person? There are couples, married for 30 years...and then it turns out that the husband was secretly gay all the time and the wife didn't know. So do we ever know another human being 100%? How could we? We don't even know ourselves 100%, given that our mind is very easy to deceive us. So how could anyone else know us that well?

In my opinion, it should be enough to just check if both people like each other. All that crap about getting to know each other seems to be just a manifested, build-in obstacle that become common courtesy in todays dating world. There's still time for that later, right?
Even more so, wouldn't it be much better to take things faster? If you meet someone you like and then you jump right into a relationship and find out it doesn't work after a few days only and you're hence back on the market...isn't that much more efficient than wasting weeks, months or even years to find out just the same thing?

I just wish we as human beings could be more rational and more pragmatic and practical-thinking about this. I'm really no fan of all the stalling. If I like someone and that person likes me, that should be ground enough to take further steps...or not;)