It isn’t about a dream while being awake. It is about viewing the symbolism of the situations I experience while awake similarly to the symbolism of the situations I experience while dreaming.
I haven’t read Seth explaining exactly what would one get from asking for true dreams from the Gates of Horn, beyond harmonizing the part of your being (if i correctly recall his formulation).
My experience with asking for true dreams from the Gates of Horn is that they bring you messages that aren’t as much symbolic as they are direct lessons you witness, and can learn from them.
The symbolism is needed to minimize distortions, but if you’re aware of receiving messages, and if you establish a good connection to your inner source of knowledge and guidance, you can bypass the symbolical translation.
You can ask for, and look the same way at the situations you experience while awake.
This seems to also stimulate your use of your inner senses like direct knowledge, conceptual view, past and future, …