I'll try to answer this...
Awareness - the fundamental nature of your mind: being aware. Luminosity. This is the attribute that all conscious beings possess.
Perception - the noticing of something. I 'see' this or that.
Awareness, in the way you are mentioning it, is like hearing something, but not knowing you are hearing it. Seeing something, but not knowing that you are seeing. So in a way, this could hamper your experience; your attention to the object, your ability to interact and to know it, is hampered by lack of directed attention, lack of giving it proper notice and considering it.
Mindfulness (sanskrit: smṛti, another Buddhist idea) is the noticing of this awareness. It is also translated as 'awareness', but it's awareness with an intent, purpose, or object. It does take effort to be mindful and to perceive, absolutely! But it's effort well spent, from my outlook. Most of the time we are aware, but we're not meta-aware (aware of our awareness). That's mindfulness, that's smṛti.
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