Is ablation the only option available for afib? How effective or successful is it?

It depends. Medications are usually first line therapy for atrial fibrillation. If your afib is bothersome, and it can not be controlled by medications, then considering a catheter ablation is reasonable. The success rate varies depending on how long you've had af, and other clinical factors, but is usually around 60-70%. This is typically a better success rate than medications alone.
No, Somewhat. No - there are medical therapies and surgical therapies as well. First ablation procedures w/ current technique are generally 50% effective at eliminating either the rhythm or all symptoms of the rhythm. With a touchup procedure, that generally goes up to ~70%. Many electrophysiologists like to claim higher rates, but these numbers reflect the best published data from some very good centers.
No. Ablation is a procedure where a catheter is inserted through the vein and an area of the heart receives rf waves destroying the tissue causing/allowing the atrial fibrillation to occur. Conventional therapy is rate control with medicine such as digoxin, beta blockers, or calcium channel blockers and maintaining regular rhythm with antiarrythmics. If failure then ablation is used with 75% success.
Agree. I agree, the rates are low, around 50%. It also depends on the type: chronic afib has a lower success rate as opposed to new onset or paroxysmal afib.
No. Other options are medications to control the heart rate, blood thinners to prevent clots, medications to convert the rhythm back to normal or to keep the problem from recurring. A large study showed that patients can do quite well even if they stay in atrial fibrillation. Ablation success varies but the results are improving.