
They are- they can be removed, stripped, cleaned and refletched. The FF187's are very durable, I've had a couple buried up to the fletchings in the target without damage.
X10's have a fairly thin aluminium core with a very thick layer of carbon, they behave more like a carbon arrow than an aluminium one. Best of both worlds so to speak.
And the shooter is the biggest error factor, that doesn't stop improved equipment from helping. When you're talking about trying to hit a 4" circle 90m away in strong winds, then better arrows certainly help. I noticed improvements on my groupings from going from Powerflights ($70 doz) to Carbon Ones ($150 doz) to X10's ($530 doz). When you're talking about a very small handful of points separating you from being say, number 3 in the country, to number 20, the investment is worth it.