Compare two people who meditate. One person does it whenever s/he feels like it. Another does it at an appointed time each day, whether s/he feels like it or not.
The difference is very big. The second person has surrendered to something other than the will of the moment (whether it is something “higher” is open to question). For her, what prompts meditating is not a feeling, but a commitment.
For this person, it’s not, “I feel like meditating now.”
It is, “It’s time for meditating now.”
For the second person, meditation has become meaningful as ritual. Interesting that when someone does something on a fixed consistent schedule (it could be checking the stock market or going to the bathroom), we say, “He does it religiously.”
Perhaps the ritualistic kind of meditator could even be said to retract her own will in her practice, because her practice does not issue from the feeling or desire of the moment. Perhaps it is a diminishing of the ego. You can feel this kind of quality in full force in some writings by very spiritually developed people, for instance Thomas Merton.