What are benefits of adopting kernel modules in the modern Linux kernel?

Answer 1

Efficiency. Thanks to modules, the kernel doesn't have to have every last driver loaded and running, nor does the user have to recompile the kernel every time they need to load or unload or update a driver.

Before the Linux kernel adopted modules, one had to recompile and reconfigure the kernel any time they wanted to change drivers. Today it's as simple as unloading and reloading modules.

Some people, however, like to disable modules and build everything into their kernel when they create a custom Linux kernel. This is done largely because when someone makes a custom kernel there is no question what drivers and pieces of the kernel will be needed, and modules would be unneeded.