Same here. Both, CPU and GPU radiators can be placed on the case on the way, that heat is immediately sent out of the case. Also bigger radiators can be used.
Actually water cooling is just a more complex air cooling. Heat is carried with liquid into radiator, where liquid is cooled down and sent back to collect heat. If you want easier to manage solution, then air cooling is better option. But if you control more precisely cooling and noise then liquid cooling is better option, as you can play with pump speed, fans speed etc simultaneously.
I personally recommend to use OOB liquid cooling as these are easier to install and maintain. No risk of leaking usually. Below is an example of Z390 with alphacool OOB type coolers. For cpu is used 420 radiator, which gives bigger cooling area and provides more silent system. GPU has also water cooling.