I think it's more of an internal quality control issue as opposed to being for the customer. I believe that companies record phone calls as a form of protection against lawsuits. With a recording there is no "their word against ours". Also it helps the management of these companies know whether or not the employees are keeping protocol during their interaction with the customers.
The phrasing of the recording is to make you (the customer) feel like the recording is for your benefit, and this may be partially true, but it is truly for the company itself.