When do we need GCPs

I am new to drones and wondering what type of output would require GCPs or geo referenced images. Do I need this even if I need to create orthomosaics using Pix4D

I am using GoPro 4 with 3DR solo

Dear Ruchit,

GCPs and georeferenced images will be useful if you want to be able to position your output on Earth, i.e. have the exact coordinates of features, or export it to Google Earth for example. 

They are not mandatory, but would improve the accuracy. Image geolocation also improves processing time as the software can place the images with respect to each other (more or less) and has more prior information for matching the images. 

Best regards,