In the early days, obtaining awards often required you to send copies of your QSL cards to organizations for evaluation. These awards were based on ITU and CQ counts, so amateur radio operators would print their two分区号 (partition numbers) on the cards to clearly identify the source and facilitate counting. Nowadays, many competitions or award programs recognize LOTW and other logs, making physical QSL cards optional. Therefore, whether or not to print the partition numbers is no longer important. Personally, I recommend including them for two reasons: 1) to preserve tradition, and 2) because there are already very few characters on the card, so it's easy to add them. This can also test your layout design skills.