Yes, the attributive form (連体形/名詞修飾形) of a verb looks exactly the same as its dictionary-form (終止形/辞書形) in modern Japanese. But that was not true in archaic/classic Japanese. From Wikipedia:
... modern Japanese verbs have the same form whether predicative or attributive. (The only exception is the copula, which is da or desu when used predicatively and na when used attributively.) Historically, however, these had been separate forms.
So for historical reasons it's worth distinguishing the two.
And 連体形 and 終止形 are still different in na-adjectives (i.e., 簡単な本 vs この本は簡単だ), so thinking them as different things is a good idea for the sake of consistency.