From the package’s documentation:
Intel® 64 and IA-32 processors (x86_64 and i686 processors) are capable of
field-upgrading their control program (microcode) as well as parameters
for other on-chip subsystems (power management, interconnects, etc).
These microcode updates correct processor errata, and are important for
safe, stable and correct system operation.
While most of the microcode updates fix problems that happen extremely
rarely, they also fix high-profile, high-hitting issues. There are enough
microcode updates fixing processor errata that would cause system lockup,
memory corruption, or unpredictable system behavior, to warrant taking
firmware updates and microcode updates seriously.
So yes, you should enable this option. It won’t improve your CPU’s performance, but it will fix bugs (including disabling TSX on Haswell and Broadwell CPUs, where it can cause lockups) and it might enable new features (such as Software Guard Extensions on some Skylake CPUs).
Note also the caveats listed in the same documentation, in particular
Please keep your UEFI/BIOS up-to-date. Assuming your motherboard vendor
does a good job of updating system firmware components, an up-to-date
version of the firmware will negate most of the caveats listed here.
This is particularly true for recent CPUs, starting with Haswell. Nowadays keeping your UEFI/BIOS up-to-date is a good idea for security reasons too.
It’s also worth keeping a copy of the recovery procedure given in the documentation, in case a microcode update causes issues when booting your system.