As we all know, if you translate the word moorti, it will be translated as idol or sculpture. Yet that seems to be used loosely. Take for example, Ganesha is referred as Mangal Moorte, and in the Doha of the Hanuman Chalisa, it says Mangala Moorte Roop.

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Moorti in Sanskrit means embodiment or image.
But then what's an embodiment?
An embodiment is the physical or spiritual-physical form of an entity. Much like a symbol. Take for example, if you have an empty glass, then it would just be a glass, but if you pour some water into it, then it would become a glass of water.

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Let's use Mangal Moorte Ganesha, and Mangala (auspiciousness). Auspiciousness is a formless entity. No one can touch it or see it. Since Ganesh is the embodiment of auspiciousness, then auspiciousness has gone from formless to defined. Defined as in one can recognise it. This means that the recognition of auspiciousness is Ganesh himself.

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Yes a moorti is a moulded and consecrated pratima, but it is used to change the deity from Nirgun to Sagun. From formless to having physical characteristics.
The Nirgun form of Bhagwan lives in our Hriday Mandala. Hence, seeing the moorti, one will be entwined in the Nirgun and Sagun forms of Bhagwan.