Last but by no means least: the looks. Tan sidewalls are incredibly popular when it comes to gravel bike tires, although they won't be everyone's cup of tea. Many of these tires will be available in black too, or some even with coloured treads or sidewalls.
Make sure you wash your bike regularly — probably every ride in the winter at least — to keep your components happy and your tan sidewalls looking fresh.
Keeping your bike clean also gives you the opportunity to carefully inspect your bike up close, which can help you identify any potential issues with your tires or let you know when they need replacing. And keeping your bike cleaner will help it work better so, yes, tan sidewalls will really help you to ride faster.