The advantages of Thunderbolt 3:

The primary selling point of Thunderbolt is that it is an interface that combines PCI Express and DisplayPort into two serial data stream, in addition to DC  power.
Support of USB-C or USB-type C
expanding computers  capability while reducing cables and other interface ports
Thunderbolt 3 supports a transfer rate of up to 40Gbps
Graphics based expansion capability, must better than USB based graphic expansions
Thunderbolt 3 allows daisy-chaining of up to six devices