15 R4, why update drivers?

In addition to my general statement above, here's one example applicable to your Alienware 15 R4.  This is a recently released update to the Intel Rapid Storage driver and application.  As you can see from the release notes, it adds support for something that can improve battery life, fixes a security vulnerability that existed in the application installer, and adds support for a new Optane feature that might be useful to some people: https://www.dell.com/support/home/us/en/19/drivers/driversdetails?driverid=thvt6&oscode=wt64a&productcode=alienware-15-r4

You don't wait to install Windows updates until you get a new PC, do you?  Drivers are similarly updated for many more reasons than adding support for newer generations of the device's product family, such as:

- Improving stability, reliability, and/or performance

- Resolving problem conditions that might arise when certain other hardware or software is also installed in that system

- Adding compatibility with newer versions of Windows 10, or adding support for new capabilities introduced with that new release.  Those releases arrive roughly every 6 months nowadays, and as one example, the Insider builds leading up to the upcoming Windows 10 1903 break support for Creative X-Fi audio devices, and Creative has only recently started issuing driver updates for various X-Fi products that resolve that issue.

- Fixing bugs that create security vulnerabilities on your system because they can be leveraged in an exploit.

Fyi, the release notes of a given driver update will often list fixes and/or enhancements, although those notes aren't always comprehensive.

You have a system with an 8th generation processor so it is relatively new. Intel and Dell will be working on improving the drivers, to fix minor problems and to address security risks. Moreover Windows 10 is continually updated to new builds, and if there are any changes, sometimes complementary driver improvements are made for newer Windows 10 builds.

What's the sense in getting one of your knives sharpened when you have not bought a new set of knives?