The quadcopter design is much simpler and cheaper but less stable (before electronic stabilization) and efficient than a helicopter. The popularity is probably

The quadcopter design is much simpler and cheaper but less stable (before electronic stabilization) and efficient than a helicopter. The popularity is probably due to a combination of easy handling (with modern gyros/electronics), robustness, low cost and the trend to film everything. Helicopters are difficult to control and more suited to serious applications (carrying weight, long flight times...).