The description of designated goods and designated services is what the applicant declares, "I use the trademark for this goods or services."
Since business credit is accumulated only in the trademark that the applicant actually sells the goods and services, even if the trademark is the same, if but the goods and services handled are different, the customer will not be mistaken, and can be registered.
In addition, in order to prevent damage caused by people who try to monopolize trademark registration in advance or who try to sell trademarks to others, there are some rules that mean that designated goods / services should only list the goods / services that have actually started the business (planned to start the business in the near future).