.config file in
/boot has any role other than an information about the modules' presence? A
.configXXXX in linux kernel source tree is used while building the kernel to ON/OFF a feature. But after installing what is it's role in
In addition to Stephen's answer I have to say that if your distro does that, that sounds old-fashioned and inefficient.
The preferred way of storing the kernel configuration nowadays is the
vmlinuz file and then you can get the config from
/proc/config or extract it from
vmlinuz, so there's no need to have/install an extra file on your disk.
The file itself is indispensable as it allows the user to understand what kernel features are enabled/disabled and this affects how the kernel works or what features are available (e.g.
iptables which are disabled by many forward-looking distros).
For the kernel to work, there has to be zero files or storage devices. The bootloader may download/run
vmlinuz and the root filesystem from the net/USB/ROM/whatever.