Charges tickets or accounts

What is the benefit of creating a ticket to add charges instead of just adding charges directly to the accounts?

It all depends on how you invoice your customer. In case you invoice them at the Ticket level (e.g. an invoice per Ticket) or at least your customer wants you to list to which Ticket each charge included in the Invoice (as an Invoice Line) is related to then log Charges under Tickets. However, if you simply log invoice your customer at the customer level, or if some specific Charges are not really related to a Ticket (like when the customer buys something) you can simply add the Charges at the customer Account level.

HTH