Tire prep compounds are created for working on even and hard surfaces like concrete, asphalt, or synthetic material. That is why you will get max potential out of a formula on the race trails.
As the indoor karting track surface is made of similar materials, tire prep formulas certainly work on indoor trails for increasing tire traction.
Indoor karting trails are frequently made of concrete using a screed and finish later on the top.
The finish is created for providing a fantastic degree of traction for rubber tires. That is why the formula is not really utilized much indoors.