There is an essential difference between awakening through realization and awakening through understanding

Intellectual understanding (解悟) is like guessing the general way in which the tathāgatagarbha functions; it is not observed through direct perception/valid direct cognition, and is not as clear as seeing an object right before one's eyes. What is arrived at by guessing leaves the manas still unclear, so the mind is not settled—it does not come to rest—and can easily be swayed. In such a state, one cannot observe the concrete operation of the eighth consciousness and cannot give rise to genuine great wisdom. Ordinary conceptual comprehension differs greatly from the level of intellectual understanding, and the gap between intellectual understanding and realization may be very large, depending mainly on how well one's usual conditions for the six pāramitās are cultivated.