The main benefits of an RTD sensor (Pt100, Pt1000) is the good accuracy over a fairly wide range and combined with excellent stability, this is in contrast to a thermocouple which is less accurate, less stable and can drift over time.
RTD Sensors are more suitable for lower temperature ranges, where higher accuracy and repeatability is needed. They also need to be immersed in the media due to stem conduction errors. A practical benefit of RTDs over thermocouples is that they use standard electrical wiring, where thermocouples require compensated alloys and connectors over the entire length up to the connection of the instrument.
Most modern measuring instrumentation will have all the standard thermocouple input types such as Pt100 or Pt1000 for RTDs and K,T,J, N or R & S for thermocouple, although distance and positioning are more important when selecting a product.