Couple of fun and useful things on the benchmark. Firstly, if you want to use your own character's hairstyle but can't because it's not a base hairstyle, you can do it. (These aren't my videos, they're from Meoni who makes a lot of FFXIV update content).
Second, if you want to see a fun easter egg, set your system date to April 1st, then open the benchmark and run it with the default character (I.e., not a custom one, just basic Derplander). Or watch this video to see what happens.
I play on console so haven't been able to try the benchmark personally but am very excited for DT to drop!