Sometimes the testers make a mistake and choose a different browser than the one in which the bug occurred. After submitting the report, it is no longer possible to change the browser, so the tester must either submit a new report or try to reproduce the bug in the browser that was mistakenly selected.
In the first case, it takes time, especially since it may happen that later a duplicate of this bug will be provided by another tester. Thus, the tester loses money for a valid bug.
In the second case, this is not always possible. For example, the bug only happens in Safari.
Therefore, the ability to change the browser in the report will improve the user experience and reduce the suffering of testers.