That's because it cheats! Arabic script has three layers: 1. The base forms (rasm) denote groups of consonants. 2. Then dots distinguish individual consonant

That's because it cheats! Arabic script has three layers: 1. The base forms (rasm) denote groups of consonants. 2. Then dots distinguish individual consonants (e.g. B, T, TH, Y and N have the same basic form but have different arrangements of dots). 3. Finally, diacritics - loops and dashes - are used to denote vowels. When Arabic is fully laden with vowel markings, the result is visually noisy. So usually vowel markings are left out. But without vowels, it is impossible to tell how a word is pronounced if you don't already know. It's a really heavy price to pay for any advantage in reading speed.