Before diving into the question, first I have to emphasise that if we didn't have dreams it would be actually pretty hard to establish a healthy communication about this topic. Take simulation for example. People frames similar ideas with concept of simulation. However is it even relevant. You are experiencing a simulation when playing computer games. Yet via inputs taken by your medium in this life. Simply existince of a simulation is not even relevant. It is just what you feel and experience. That is the only thing you know exists for sure. Whether what you assume as ultimate reality is also dreamlike phenomena or not. Only thing you know is you experience.
It is clear that it is not possible to clarify exact nature of what we overall perceive as ultimate reality. It is possible to realize that you are in a dream in a dream maybe we can say because dreams are less realistic and flawed in some terms. However that doesn't make current experience the ultimate. We can't even know what we can know beyond the scope of this life if it is also dreamlike phenomena. And the default case should be that this life is probably just a dreamlike phenomena simply because only experience we relate to this life is dreams. And when you are in a dream you don't know whether you are in a dream or not. Although some people realize that it was a dream within their dreams still even than they don't know it until the moment they realize it in their dream. Our brain work over relating concepts over other concepts that ultimately all derives from more fundamental concepts and their combinations. When it comes to the reality we have dreams and normal life. Just because in normal life we feel like normal life is real, which is also the case when you are in a dream, doesn't actually mean dreams are less real. And over this you can relate that daily life is also probably a dreamlike phenomenon. If you weren't able to dream you couldn't even think about it. It is really interesting that dreams exists at all. And the way you remember dreams is also really weird. There are almost restrictions. Overall anything about dreams are very absurd. What you remember in your dreams about yourself is also not same as when you are awake. For instance I wasn't eating bakery since more than five years. Yet I frequently eat bakery in my dreams with great apetatite. Interestingly the reason that I remember this frequenly happens in my dreams is because I realize something is off when I am eating bakery in my dreams. Which clearly triggers a strong possibility of awakening and leds me to remember those moments. Normally I don't have good recall for my dreams.
Our brain is barely in our control. We can decide our actions. But we can barely control what we think. Our brain force us to think things relates to survival. If you are doing something potentially dangerous like driving a horse or a car or any doing any physical activity you don't struggle on focusing. However when you are idle you brain starts coming up with ideas regarding potential threats. And abstract tasks of modern life sometimes becomes impossible to focus on. It is not just anxiety. Your brain just doesn't care. Severity depends on how your brains relevant circuitry schemed in you development. This conditions called ADHD. However it is not a disease that a group of people has. It is a problem that almost everybody have at a scale. For a construction worker it is not an issue but for an academic or an engineer or any student it is.
It may sound like I got little bit distracted the topic. However the issue is exactly this because our brain constantly force us to think about certain way. We can't actually think clearly about this world. If we were able to, it would be pretty horrific. Imagine thinking straight. You can experience very painfull disease at any moment. You can lose anything that makes you happy. And this will end. Putting scary parts aside. Because it will end in short amount of time. That doesn't make it valuable by itself. If you think that is the case I don't understand how you were able to read so far. But anyway. If you were able to think straight with using pure logic, the possibility of this life being a dreamlike phenomenon would suddenly become only important thing. Even if it is not the case, there is nothing else.