People have already pointed out the legal and financial aspects. But I also want to address the philosophical aspect of your question, which I think you had in mind. And I think the answer I would give you is this one:
Marriage has the meaning that you assign to it.
I strongly believe that if we got rid of any legal and financial benefits of marriage, even if we made it explicitly illegal, there would still be a bunch (or even a lot) of people who would get married.
I would compare it to a house fire. If my house was burning (and there were no living beings in it) and I could save 5 things, what would I save? What would you save? I would take, for example, my favorite soft toy from when I was a kid, and my old box filled with diaries. Is this worth any money? No. Does it have any value? To me, it does. To you, it doesn't. Maybe you are a very rational person that isn't attached to anything (or to nothing material) and you would indeed make the smartest choices, saving your passport and documents and money. Maybe you would save a small gift that someone important has given you. Maybe you would save the first guitar you ever bought. You save whatever has value and meaning to you. And these things have solely the meaning and value that you have attached to it.
Likewise, people have different value and meaning attached to marriage. If you look at it from a rational, logical side - it has its legal and financial perks and benefits and if they weren't there, getting married would make no sense. But things don't have to make sense. The meaning we assign to rituals, things, concepts, aren't necessarily rational. They are, however, deeply personal.
So, as a side note, please beware of ridiculing people for their views on marriage or weddings, just like you wouldn't want to ridicule or belittle someone for other things that mean a lot to them. Always sharing the last piece of bread. Always giving a coin to a homeless person. Having a breakfast for 30 minutes every morning. A good night kiss on the nose from their partner. Drawing a dick in the first snow of the winter. Some things mean a lot to people even if they do not rationally make sense.
In the case of marriage, of course, some of the meaning comes from culture, history, and tradition. Marriage might have had different purposes than it has now, and surely the origins weren't that romantic. (Not saying, however, that marriage has to be romantic.) But it is there. It is important to some people simply because they have, at some point in their life, decided it is important for some reasons, rational or irrational, social, cultural, and hopefully personal too. To them, it makes sense, it has meaning, it has value. And whatever marriage or a wedding ceremony mean - you decide.
So the question you should be asking is not whether or not you should get married, it is what marriage means to you. Does it have any benefit or value in your eyes? Are the legal benefits enough for you to get married? What is your stance on divorce? Do you feel like you would get "closer together" with your partner? Would you feel it would make things harder to separate? There are a ton on questions like these that you can ask yourself, I hope you get the jist. There are not right or wrong answers. The only thing that is important is that the meaning you assign to marriage is (about) the same as the meaning your partner assigns to marriage. You can both not care about a spiritual meaning, but just get married for the benefits. You can both be a type of "whatever happens, we don't get divorced, til death do us part". You can be "we'll keep reevaluating whether we still belong together". You can also be "we get married because we have children and this is practical". Or "we get married because I am hot and you are rich and when one of us loses their asset we split". Or "we just want a fancy huge ass party to show our love in this very moment and celebrate it with our friends and whatever comes afterwards is secondary". It doesn't matter what your view is, it matters that you guys agree.