Effieciency creating accounts and enrolling accounts into courses using moodle

This is a semi-frequent task that falls into my moodle lap.  I get an email from one of my customers who says "james, I have xx people who need to be enrolled in this course xxxxx, please and thanks".

My first though is,

"should I enable user authentication on the site? Allowing people to come to the site, create their own accounts and enroll themselves into a course - with an enrollment key."

 My second thought is

"This is not the best service, and would probably be more problematic with issues like, I could not create my account, or I don't know where to specify the enrollment key". 

I do like the idea of allowing users to create their own accounts - but, I often think I create more work for myself and it feels lazy.

What I ended up doing was formatting the provided xls file to the moodle specifications,
including enrolling the accounts into a cohort. These are the specific steps I took

Steps to create new accounts and enroll accounts into a cohort

1 - Create the cohort in moodle
2 - Enroll the cohort into the desired course
3 - format the customer provided xls file, to the moodle specifications (this is the most time consuming step - data scrubbing)
4 - find my sample file that I used last time I did this, to help with step 3
5 - save the xls file as a csv file
6 - As site admin  - go to Users | accounts | Upload users
7 - Browse to the csv file
8 - Upload it and review the *preview
9 - compete the upload.

Step 9 creates the new accounts - with the default password of changeme, which moodle forces a password update on the account upon initial login.  Also enrolls the accounts into the cohort.

A snapshot of the formatted xls file that I save as a csv file.

 Notice the first row of the file, also the user names in the file are first letter uppercase, which the preview step will complain about, but moodle will convert the username to lowercase upon.  Also - note there are no spaces in the cohort name and the password is changeme.

Not bad - total time, about 30 minutes.