Holding 2 wp_user in the same action (to update billing_email when user_email is updated)

I was frustrated by the same thing in WordPress.
Check out my unanswered question: Content hooks vs User hooks

I ended up getting around it by matching the user id and updating all the user fields regardless of whether they were updated.

Until WordPress treats users’ hooks the same as posts’ hooks I think we’re stuck with subpar processes.