I love it's sparkle, but there are more opulent ways to get that nowadays.
It can be messy, but nothing fills an empty tree with the colour of Christmas quite like it.
Just like the poll ATM, I can side for or against.
My tip...use it to stuff the inside of your tree branches before decorating with your baubles and ornaments, that way, you can have a slight glimseof shimmer lit from within against your lights, and reveal enough background colour to really highlight your decorations. Almost as if trying to hide it amongst your branches, you really only want to see as little as possible, and once you decorate, you'll be amazed how much it still adds to the finished result.
This is great to do while you are slowly filling your tree with expensive ornaments, and when you get enough of those you can remove the tinsel altogether.
I haven't needed tinsel for years now, but it was there when I needed it.