Hizb 4 is the second half of Juz 2, and its final rub al-hizb quarter ends within a single verse of one of the Quran's most recited passages, the Throne Verse at 2:255, which instead opens the material carried in Hizb 5 at the start of Juz 3. That near miss is a useful reminder that the sixty-part scheme was never designed around which verses later generations would come to treasure most; it was designed to cut the text into equal lengths for a reciter to complete in a set number of sittings, and a famous verse falls wherever the count happens to leave it.
In a tarawih schedule of one juz per night, this hizb typically closes the second night's recitation, and its own four quarter marks let a reciter judge how much of the night's portion remains through a stretch of legal and narrative material, divorce law, the story of Talut and Jalut, considerably more varied in subject than the legal material that opened Juz 2.
For memorisation review, finishing this hizb cleanly and beginning the next with the Throne Verse gives a hafiz a natural, memorable marker distinct from the juz boundary itself, one of the places where the mechanical division and a reciter's own sense of the text's high points happen to sit close together, even though nothing in the hizb system was built to produce that effect.