Client Membership gives access to the Client Admin. Section Membership controls access to each individual section.

Creating a Section Membership within a Client Membership and then assigning it to a user in Client Members allows you to automate the membership to that user. The user will then be automatically set as that membership in whatever section they enter from there forth. 

Creating a Section Membership and assigning it to a user within a given section is manually setting a users access to that specific section. 

Go back to How To Use Memberships