I do the same thing. Slows down the fall. I think it offers a realistic/tactical approach to ukemi as well. It encourages nage to have good posture too.
In Judo, I struggle with this, because holding on can be detrimental to you and give Ippon to your opponent. But that is the strategy of the judo game.
I think holding on is the way to go most of the time. Once I have a grip on you, I am taking you with me, so you better have good awareness and posture.
You ol' cheater you......