If additional compensation isn't offered, does it affect the employee in any way?

No, it doesn't as the salary agreed upon should have been inclusive of remote working expenses. The employee will receive the exact same net amount each month as before.

The only difference being that a certain amount will be allotted to compensation for expenses. For example, an employee that receives a net amount of €1000 euros per month, going forward their payslip will indicate €940 allotted to salary and €60 to compensation for expenses.