Yes of course. Ilm al-Rijal is the knowledge which makes us know the trust worthy person from others. Allah orders us in Quran to verify any information or news and not to take it blindly. Sura 49, Verse 6. With out proper verification things will be mixed and we will not know which narration is authentic and one is not. Liars in history till today are too many. Thousands or more narrations were fabricated for political reasons and other worldly reasons. Ilm al-Rijal enables us to verify and avoid false narrations and take and act upon authentic narrations narrated by pious trustworthy persons.