Xerath is pretty hard with manual play since all Q, W, E, R are skillshoot which mean you cannot just click on an enemy to cast it but you need to manually predict the enemy movement and shot a direction or a small location. But with scripting it is a perfect poke machine. (poke means using long distance abilities to attack without taking close to enemy risk)
This youtube clearly shows the power of Xearth scripting:
You can see every Q, W, E, R is so fast and so accuracy, especially R is so perfect and lightening fast which is almost impossible for human to do that. It is even more impossible if Xearth kills someone with first shot of R then in next 0.1 second kill someone else on the another side of the map. Xearth dodge anything even close to him is another sign of scripting.
When you play Xearth scripting, just keep a good distance and keep poking with your Q, the enemy can do nothing about it since Xearth Q has like the longest distance. Do that 1 on 1 and also team fight later, the other team can just keep gong backward and keep losing health. When someone is killable just walk away a little bit and cast R. W, E would auto lock anyone tries to come to you.
You should has the most damage to champs for almost every game. With 45% CDR less than 3 seconds cool down Q and less than 1 minute ready R the other team can just do nothing about it.