Pretty much this. As a quant / data scientist, I quite often have notebooks just hanging there for weeks with a few hundred GB of ready-to-use data preloaded an

Pretty much this. As a quant / data scientist, I quite often have notebooks just hanging there for weeks with a few hundred GB of ready-to-use data preloaded and preprocessed in the kernel which makes the experimenting with it incredibly ergonomic. Being able to quickly check the output while iterating on a an algorithm, or visualise intermediate results is irreplaceable.