I like the idea of a business you join which then you can hold to account. The shares issues to me is very weird.
Shares are a financial gamble. The idea that you buy a share and then you own a part of something which you can then trade with others to make money? apart from money their is no commitment towards the company you have the shares in. no partnership.
Membership is a force for Good and change. It is also a commitment of intent in someway. A seeking to engage, be led and influenced while leading and influencing the organisation back.
The Co-Operative have several campaigning strands to how they operate. I am not sure i agree with all of them, I am not familiar enough with them to say I support them all, but I do agree with the idea and principle of a business actually campaigning for something out with their own self interest.
The benefits of membership are explained here
You should join. Go on it’s literally free.