  This is a contribution for the discussion on "Unbiased Markov chain Monte Carlo with couplings" by Pierre E. Jacob, John O'Leary and Yves F. Atchad\'e to appear in the Journal of the Royal Statistical Society Series B. 
Discussion of "Unbiased Markov chain Monte Carlo with couplings" by   Pierre E. Jacob, John O'Leary and Yves F. Atchad\'e