Japanese pronunciation is mora-based (correct me if there is a better word), i.e. each mora is pronounced with equal length.
Still I sometimes see the concept of syllables used, e.g.
疲労 /hirō/ 'fatigue', 2 syllables /hi/ and /rō/, 3 morae 広尾 /hiroo/ (location name), 3 syllables /hi/, /ro/ and /o/, 3 morae
The justification for the 3 syllables in /hiroo/ is that there is a morpheme boundary between /hiro/ and /o/. However, in my opinion the 2 words are pronounced exactly the same.
Assuming that I am correct, what purpose does the concept of syllables serve? I can see that in other languages, it might make sense to distinguish between long vowels and double vowels (e.g. the former might be approx. 1.5 times as long as short vowels, the latter twice as long), but since Japanese is mora-based (i.e. both are twice as long), does the distinction serve any purpose?