pixel_player329312103 You use the caravan tickets with materials to buy experience, so that you can level up & get energy like that. Depending on the region, there are different options. You can check the list here:
For example, I'm in Greece & if I send a caravan ticket & 1000 adamantine steel, 2 hours later I'll get 82,5 million xp, that will get me almost 4 level ups at the moment & at least 2,5 million energy from them.
You should only use the tickets with materials you don't need anymore. Also, for Double Production Week, the xp is doubled, so it's best to save them & use them then.
Also, it's best to save the precious stones (rubies, topaz, etc) for the specialty event equipment that's available sometimes in events. The first time the caravan tickets were introduced, I spent my amethysts, but later I regretted it.
I hope this helps 🤞