获益 is a formal verb-object (离合词) meaning 'to gain benefit or profit'. The object 益 can be separated from the verb 获 when inserting measure words, 了, or modifiers — for example, 获了不少益 ('gained no small benefit'). You often see it in set phrases like 获益匪浅 ('gain much benefit'). The word is more common in written or formal contexts than everyday speech.