Convenience: Regular batteries are widely available and can be easily replaced in the field. This means that you don't have to worry about running out of power when you need it the most. On the other hand, rechargeable headlamps require a power source to charge, which can be difficult to find in remote areas.
Cost: Regular batteries are generally less expensive than rechargeable batteries, especially when you factor in the cost of a charger. This means that you can save money in the long run by choosing a headlamp that uses regular batteries.