Normally, no special feedback is necessary during delays of more than 0.1 but less than 1.0 second, but the user does lose the feeling of operating directly on the data.
My freedom will be so much the greater and more meaningful the more narrowly I limit my field of action and the more I surround myself with obstacles. The more constraints one imposes, the more one frees one's self of the chains that shackle the spirit.