In seismic acquisition (when you acquire "pictures" of the subsurface, much before the drilling part) you need accurate positioning of your sources & sensors.
Geological mapping (actually all mapping) is easier and more accurate with high precision high accuracy position data. The more accurate your map the better your geological model etc.
Also drilling is done to extremely high precision these days.
Edit: Bare in mind the industry uses differtial GPS for some tasks - this can give mm/cm precision.
The other answers here are probably right about the use case here, but keep in mind that "oil/gas exploration" is often among the first uses of a new technology.
There's a ton of money in oil/gas, and any technology that can give a slight edge is often worth it. For example, oil and gas companies were some of the first to use Iridium (worldwide satellite internet at ridiculous prices), and I'd bet that they are the biggest users of the Iridium network to this day. This goes for inventions in tons of fields.
For example, new breakthrough in diving: great, you can use that to work on underwater parts of drilling rigs. New breakthrough in robotics? Great, you can replace the expensive and dangerous dive crews with underwater ROVs. New breakthrough in geology? Cool, you can use it to find oil.
Seismic exploration of new oil fields requires both accurate geographic and, maybe more importantly, accurate time synchronization. If you place a ton of sensors in the ground and then pound the ground or set of explosives you need to know exactly where and when the echoes of the sound waves were picked up.
I'm pretty sure this is it. They have a drill that is essentially an anchor and the rest of the platform is essentially a floating quadcopter maintaining position.
I wouldn't expect interesting oil/gas pockets to have <5m lateral diameter, but then again I know very little about that industry.