No, there's nothing wrong with hiking alone if you're well versed in map and compass work, and have a proper topo map of the area you'll be traveling through. This particular trail crosses some barren lava flows where the trail is marked with cairns and some people have gotten lost, but I wouldn't hesitate for a second, because not only am I confident in my ability to stay on the path, I am confident I could find the path again if I got lost or failing that find my way to a road if I got lost, and failing that if I got lost and/or hurt I could survive a night out, or two, and await rescue, and failing that I would be happy to die doing something I love somewhere beautiful in nature. In fact I get "lost" all the time, but so far I've always found my way back without needing rescue, so it doesn't count against me, but towards my wilderness skill.
