One of the uses I gave to this minimal configuration is kernel development.
One of the benefits of using this .config file is that the compiling time is drastically reduced and also the code size of the kernel is reduced.
To run qemu with the bzImage of your kernel, copy the .config to your source directory
and compile as usual (make all, maybe). Then use the recently compiled image to run QEMU
gr00vy@kenny:~/OSDev/Qemu$ qemu -hda linux-0.2.img -kernel ../linux-184.108.40.206/arch/i386/boot/bzImage -k es -append "root=\"/dev/hda\" ro"