An ATA carnet limits the hold-ups and the administrative rigmarole in the case of temporary import to a minimum. This hassle is primarily connected with paying and recovering a guarantee for each country you visit. The ATA carnet replaces all of these individual guarantees with one internationally valid guarantee. This means with one single document, you can travel for one year in all countries outside the EU that are members of the ATA chain.
Using an ATA carnet is not compulsory. You can always opt to temporarily import and export your goods in the classic way. The procedures and guarantees for this differ from country to country, and you can obtain these from the customs services of the country concerned.