in my opinion it worth
in a compant have the basic information and the customer information in the company system,the company will keep the customer information safety.so in the workplace,the company will expend money to build the system,when the employee want to send a emils or use internet will through the company system,
but in a company not have ability to monitoring the employee use telephone in workplace ,it is not fair,the employee must have work spaces.but you can make a rule or communication with employee to slove ,and have told them when and where can use the telephone.