I have heard this from fellow Unitarians and from people who work and volunteer for other charities and community groups.
There are clearly rules for charities including our faith communities. We must follow these and then there is good practice - which we can choose to follow or not. But there are insights to be gained from for example understanding how businesses behave just as there are insights to be gained from psychology as to how individuals behave. We do not become psychologists by learning from psychology so we don't become business people by learning from business methods.
Whilst some of the information available comes from business sources, much comes from a more general study of organisations whatever those organisations do. The question to ask is always, 'how helpful might this be?' and not, 'where does it come from?'.
I also have a very big bee in my bonnet about efficiency. Efficiency is not about rigid structures (indeed some of the most efficient organisations have very few formal structures), it is not about the bottom line (i.e. money) and it is not about emotionless process. Efficiency is about getting something done with the least effort without sacrificing quality. Efficiency also means that things get done rather than not done, and they get done the right number of times.
Just simple examples - flower rotas, milk rotas and cleaning rotas - ensure that the thing gets done (always have a contingency plan like some dried flowers, some long-life milk and an eye that misses the dust) and they get done the right number of times. For example they avoid - two people bringing the flowers, having three bottles of milk when you only need one, or people polishing the hymnbooks because everything else has been cleaned three times. These examples are reflective of broader issues of efficiency with for example finances, meetings or developing the organisation.
Some people are fantastic at developing processes and procedures and some aren't - if you have someone who is then cherish them and set them to work helping you (that is working with others and not for them) to make the most of what you have. Less time spent on inefficient activity means more time to do something else.
As I have written a few times, efficiency is a spiritual imperative - our time, our skills and our resources are finite and I believe that we are bound to make the best of what we have been given.