- it's more time-consuming to create good evaluation questions.
- it's more time-consuming to provide a nuanced answer.
- it's more time-consuming to evaluate nuanced answers.
If the purpose of the tests is to help students retain the knowledge they've been recently exposed to, then the first kind of tests are more effective. That is, the teacher will be able to provide students with more tests, thus helping them retain more in a shorter amount of time for everyone.
It's a compromise.