For most of the pilots, the ILS approach has become a routine in their daily operations.
Besides, GPS operation is becoming the standard in civil aviation.
On the other hand, for airport operators, ILS maintenance is costly and the GBAS landing System can play a cost saving key role.
This is why GLS approaches, based on the GPS, are prone to become the standard, in the future.
This video shows in details what is a GBAS landing system.