https://www.pcgamer.com/gigabytes-16gb-memory-kit-comes-with-dummy-rgb-modules-for-those-empty-slots/

Gigabyte is shipping its first memory kit through its Aorus brand, and like a growing number of RAM products, it features RGB lighting. What's unique about Gigabyte's kit is that two of the four modules included in the pack don't contain any memory chips—they're 'dummy' sticks (or 'demo' sticks, as Gigabyte calls them) to fill out your motherboard's empty DIMM slots.

What's the point? It's purely aesthetic. The dummy modules are virtually indistinguishable from the actual memory modules—they all have aluminum heatspreaders with RGB lighting along the top.