I wouldn't really describe this as a must-have brush, but it's still very nice for detailed work.
I use it for highlighting my browbone, applying eyeshadow on my bottom lashline or smudging eye pencil.
It's especially good for connecting the outer corner of my bottom and top lashline. My eye is rounded and I have long lashes so this can sometimes be a bit tricky because I can't see that outer part really well, but this brush helps make a precise line.
I've had it for a few months and washed it several times, both with soap and makeup remover, but no hairs fell out.
It's not the softest brush in the world, but I noticed no scratching or irritation whatsoever.
Also, it hasn't lost its shape at all.
All in all, I would recommend it to those who use a lot of eyeshadow and like more elaborate looks or do makeup on others.
As I said it's not an absolute must have for everyone, but I really enjoy using it and it has proved to be quite handy on a lot of occasions.