The Artificial Lawyer poses this question in an illuminating article. It's not something I've thought of this way before. Yes, of course we want to be efficient. It's a human instinct to think efficiency is going to be beneficial. As children and teenagers, we probably wanted to study less and achieve more. But is being efficient more than that? 

To my mind, this isn't simply its definition: efficiency = useful power out/total power in. It certainly isn't the 'work harder, get paid less, increase profits' some people suspect their employer really means.  

For me, the 'power out' includes the benefit derived for colleagues and clients. By being more efficient we take unnecessary burden off our colleagues and we give more to our clients. I wouldn't go so far as to say it's obligatory but finding ways of being efficient to benefit our colleagues and clients, without a negative impact on quality of service or wellbeing, is something we should strive for in the legal sector.