Mudras are very useful during meditation. When I use mudras they give me a sense of when i’m drifting away from my physical senses. When my fingers are in a mudra and I have my eyes closed It becomes harder and harder to feel the way my fingers are situated. So I use them as a gauge as well.
z There is even an app to view mudras on your mobile device. Check out 99 mudras here

Art by Joyce Huntington