Using present tense in the evaluation section of a paper
There are several reasons to use present tense.

1) It is present time for the reader. But everyone understands the work was done before.

2) There are several versions of past tense. It simpler not to have to choose among them by putting everything into present tense.

2) English has become the international language of science. For most non-native speakers, present tense is simpler to read. In a prior era when many must-read papers in my field were written in French and German, I was always glad present tense was standard for scientific papers in those languages.