The short answer is no, dryer sheets are not bad for your dryer and it’s all a matter of preference on whether you choose to use them or not. They do however; leave a coating behind on some surfaces that need to be cleaned. Neglect this cleaning and it could affect your appliance.
How Do Dryer Sheets Work?
Dryer sheets do several things, they help neutralize static charges, soften fabrics and can leave a scent on dried laundry. The tumbling action of the dryer drum helps the sheet to work its magic. As the sheet comes in contact with items inside the dryer drum it deposits a fabric softener on those items.