If you work at an agency or very bureaucratic corporate environment and need "sign off" on specific details of a design, wireframes are probably necessary. If you're just trying to get things done and iterate- just do some sketching and then make it high fidelity in Sketch. Wireframes are a communication tool, not a mandatory design step. If you feel that a wireframe can help fill a communication gap, then use them.
If you work at an agency or very bureaucratic corporate environment and need "sign off" on specific details of a design, wireframes are probably necessary. If you're just trying to get things done and iterate- just do some sketching and then make it high fidelity in Sketch. Wireframes are a communication tool, not a mandatory design step. If you feel that a wireframe can help fill a communication gap, then use them.