What does it mean to attach a customer to an expense transaction?

geoteo

I include a customer for reimbursable expenses (disbursements). This makes it easy to have a ledger of all disbursements for each customer. However, I've noticed that you can also add a customer to an expense transaction, e.g. Meals and Entertainment. What/how is this meant to be used? E.g. flag a customer you had the business meal with? I tend to do that using the Notes.