The full setups will have the radiator at the front pulling cold air in and some fans at the back to expel the warm air. Its no worse than having the radiator outside the case entirely, in fact maybe better because you benefit from the air pressure inside the case helping to expel the warm air. The main benefit of water cooling is it can be much more efficient than fans, much quieter and you can add things like the GPU without relying on the stock fans. Saying that you can achieve just as good results with the right fan based setup but it takes more finessing.
AIO water coolers, IMO, are a good upgrade to a standard CPU fan. I know some fans can get decent results but I always struggled until adding an AIO cooler and they also free up space in the case to help airflow for the GPU.
The full setups will have the radiator at the front pulling cold air in and some fans at the back to expel the warm air. Its no worse than having the radiator outside the case entirely, in fact maybe better because you benefit from the air pressure inside the case helping to expel the warm air. The main benefit of water cooling is it can be much more efficient than fans, much quieter and you can add things like the GPU without relying on the stock fans. Saying that you can achieve just as good results with the right fan based setup but it takes more finessing.
AIO water coolers, IMO, are a good upgrade to a standard CPU fan. I know some fans can get decent results but I always struggled until adding an AIO cooler and they also free up space in the case to help airflow for the GPU.