Subliminals versus affirmations are comparing two totally different things. While both use affirmations the subliminal recordings will not be heard.
Subliminals have been proven to be more effective than just reading or listening to a list of affirmations. Let’s say you read your list of affirmations daily or listen to an audio with your affirmations recorded on it.
Your conscious mind is going to be actively thinking and reasoning while you are reading or listening. The affirmations you are reading are more than likely untrue as you read them. As you read and repeat them to yourself your mind is thinking, well that’s not true, I don’t have that, and so on…
It will reject what you are trying to tell it since it is currently not true in your reality.
Subliminals on the other hand are recorded with silent affirmations. They bypass your conscious reasoning mind and go straight into your subconscious mind without rejection.