【Harrows】SUPERGRIP FUSION SHAFT Medium Black/Aqua 's Japan Review

Why don't people use these?
I've been throwing it 2.5 hours/day for about 2 months and it hasn't broken at all.
The flights rarely come off, and if you put a flight guard on it, it always stays at 90 degrees.
I think the cost is much better than using molded flights...